U.S. patent application number 15/647612 was filed with the patent office on 2018-04-26 for apparatus and methods for orbital debris removal.
The applicant listed for this patent is Marshall H. Kaplan. Invention is credited to Marshall H. Kaplan.
Application Number | 20180111702 15/647612 |
Document ID | / |
Family ID | 59350470 |
Filed Date | 2018-04-26 |
United States Patent
Application |
20180111702 |
Kind Code |
A1 |
Kaplan; Marshall H. |
April 26, 2018 |
Apparatus and Methods for Orbital Debris Removal
Abstract
An orbital debris interception vehicle includes a satellite bus
and a debris interception module releasably coupled to the
satellite bus. The debris interception module includes a debris
impact pad, such as a pancake-shaped Whipple shield. A plurality of
such vehicles can be deployed into an equatorial orbit and
maneuvered to intercept orbital debris as it passes through the
equatorial plane. In particular, the satellite bus can release the
debris interception module before an intercept and reconnect to it
after the intercept.
Inventors: |
Kaplan; Marshall H.;
(Bethesda, MD) |
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Applicant: |
Name |
City |
State |
Country |
Type |
Kaplan; Marshall H. |
Bethesda |
MD |
US |
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|
Family ID: |
59350470 |
Appl. No.: |
15/647612 |
Filed: |
July 12, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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15448074 |
Mar 2, 2017 |
9714101 |
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15647612 |
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15352185 |
Nov 15, 2016 |
9617017 |
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15448074 |
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15333268 |
Oct 25, 2016 |
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15352185 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B64G 1/1085 20130101;
B64G 1/10 20130101; B64G 1/242 20130101; B64G 1/402 20130101; B64G
1/646 20130101; B64G 1/26 20130101 |
International
Class: |
B64G 1/10 20060101
B64G001/10; B64G 1/64 20060101 B64G001/64; B64G 1/40 20060101
B64G001/40 |
Claims
1. A vehicle for intercepting orbital objects, comprising: a
satellite bus; and an interception module releasably and
reattachably coupled to the satellite bus, wherein the interception
module comprises an expendable impact pad.
2. The vehicle according to claim 1, wherein the expendable impact
pad comprises a Whipple shield.
3. The vehicle according to claim 1, wherein the expendable impact
pad is pancake-shaped.
4. The vehicle according to claim 1, wherein the interception
module further comprises a propulsion system and a control unit
configured to activate the propulsion system to maneuver the
interception module to intercept a targeted orbiting object.
5. The vehicle according to claim 4, wherein the control unit is
further configured to activate the propulsion system to maneuver
the interception module to avoid a non-targeted orbiting
object.
6. The vehicle according to claim 5, wherein the control unit is
configured to activate the propulsion system to maneuver the
interception module to avoid intercepting a non-targeted orbiting
object by reorienting the interception module to present a minimum
cross-section along a direction of travel of the non-targeted
orbiting object.
7. The vehicle according to claim 1, wherein the satellite bus
comprises a docking probe and the interception module comprises a
complementary receiver for the docking probe, to releasably and
reattachably secure the interception module to the satellite
bus.
8. The vehicle according to claim 1, wherein the impact pad
comprises a ceramic cloth.
9. The vehicle according to claim 1, wherein the impact pad
comprises a para-aramid synthetic fiber.
10. A method of intercepting an orbital object, comprising:
deploying at least one interception vehicle into an equatorial
orbit, the at least one interception vehicle comprising: a
satellite bus; and an interception module releasably and
reattachably coupled to the satellite bus, wherein the interception
module comprises an expendable impact pad; and commanding the
interception module to maneuver such that the expandable impact pad
of the interception module intersects an orbital pathway of a
targeted orbital object.
11. The method according to claim 10, further comprising:
commanding the interception module and the satellite bus to
disconnect from each other before the targeted orbital object
impacts the expendable impact pad; and commanding the interception
module and the satellite bus to reconnect to each other after the
targeted orbital object impacts the expendable impact pad.
12. The method according to claim 11, wherein commanding the
interception module to maneuver such that the expandable impact pad
of the interception module intersects an orbital pathway of a
targeted orbital object comprises commanding the interception
module to maneuver such that the expendable impact pad of the
interception module intersects the orbital pathway of the targeted
orbital object after commanding the interception module and the
satellite bus to disconnect from each other.
13. The method according to claim 10, further comprising commanding
the interception module to maneuver such that the interception
module does not intersect an orbital pathway of a non-targeted
orbital object.
14. The method according to claim 13, wherein commanding the
interception module to maneuver such that the interception module
does not intersect an orbital pathway of a non-targeted orbital
object comprises commanding the interception module to present a
minimum cross-section along the orbital pathway of the non-targeted
orbital object.
15. The method according to claim 10, wherein deploying at least
one interception vehicle into an equatorial orbit comprises
deploying a plurality of interception vehicles into the equatorial
orbit.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. application Ser.
No. 15/448,074, filed 2 Mar. 2017 ("the '074 application"), now
pending, which is a continuation-in-part of U.S. application Ser.
No. 15/352,185, filed 15 Nov. 2016 ("the '185 application"), now
U.S. Pat. No. 9,617,017, which is a continuation of U.S.
application Ser. No. 15/333,268, filed 25 Oct. 2016 ("the '268
application"), now abandoned. The '074, '185, and '268 applications
are hereby incorporated by reference in their entireties as though
fully set forth herein.
BACKGROUND
[0002] The instant disclosure relates generally to the removal and
control of orbital debris. In particular, the instant disclosure
relates to apparatus and methods for removing orbital debris from
low Earth orbits ("LEOs").
[0003] Objects that are in orbit around Earth as the result of
space initiatives that no longer serve any function are called
"orbital debris" (the term "debris" is used herein as a shorthand
to refer to orbital debris). Examples of orbital debris include
expired spacecraft, upper stages of launch vehicles, debris
released during spacecraft separation from its launch vehicle or
during mission operations, debris created as a result of spacecraft
or upper stage explosions or collisions, solid rocket motor
effluents, paint flecks, and thermal blankets.
[0004] Most orbital debris is concentrated in what is considered
low Earth orbit ("LEO"). Indeed, orbital debris has been
accumulating in LEOs between 600 km and 1200 km altitude for the
past 59 years. The United States Space Surveillance Network,
operated by the United States Air Force, estimates that there are
more than 500,000 pieces of debris larger than 1 cm orbiting Earth
today, including over 22,000 pieces larger than 10 cm that are
actively tracked. This ignores millions of smaller, untrackable
pieces of orbital debris. Thus, the debris density in these LEOs
has reached a level of serious concern to active satellite
operators.
[0005] In LEOs, the average closing speed at which collisions with
orbital debris takes place is about 10 km/sec. Even though debris
represents a growing international crisis, space agencies have
taken almost no action to remove debris and have only limited
debris sensing and tracking capabilities for objects larger than 10
cm.
[0006] Trajectory projections, based on collected data, are
supplied to satellite owners and operators. Those few operators
that have maneuverable satellites may try to carry out
collision-avoidance maneuvers based on projections derived from
debris tracking data. Such maneuvers are rarely tried, however,
because the reaction times are short and the accuracy of collision
predictions is often insufficient to warrant an expensive and
complicated change in a satellite's orbit. Since no debris-removal
flight programs have been funded, satellite operators with assets
in high-density debris zones have no assurance of safety from
collisions.
[0007] Although collisions can be difficult to detect, over the
past several years there have been numerous reports of small debris
encounters and one reported collision between an operational
satellite and an expired satellite (i.e., the 2009 Iridium-Kosmos
incident). Nevertheless, the frequency of collisions is trending
upward, especially in the 600 km to 1200 km altitude region of
near-Earth space. In addition to the already several hundred active
satellites, several thousand more are planned for launch into this
zone in the next few years.
[0008] While the addition of debris shielding on operating
satellites may be partially effective, the collision frequency and
level of damage will become progressively less tolerable over time.
The prevention of future debris creation has been suggested, but
the debris density has already passed the point where its increase
due to ongoing collisions is unstable. Some amount of ongoing
debris removal is necessary in order to maintain at least a minimum
acceptable level of safety in orbit. A solution to this growing
threat of catastrophic destruction of all satellite assets in the
high-density debris zone has become an international mandate.
[0009] U.S. Pat. No. 4,991,799 describes an orbital debris sweeper
for removing particles from orbit. This apparatus includes a
central sweeper core which carries a debris monitoring unit and a
plurality of large area impact panels that rotate about a central
sweeper axis. In response to information from the debris monitoring
unit, a computer determines whether individual monitored particles
have impacted one of the rotating panels.
[0010] U.S. Pat. No. 3,277,724 is directed to a device for
measuring the mass and velocity of meteoroid particles which
collide therewith. The device consists of two inflatable spherical
structures, one of which is concentrically mounted within the
other. The collision of particles with the device results in a
short circuit between adjacent metallic layers, which in turn
provides an indication of the mass of the debris particle which
impacted the device.
[0011] U.S. Pat. No. 3,004,735 discloses an inflatable panel
adapted to be towed behind a launch vehicle to determine the debris
particle environment in the vicinity of the vehicle. The energy
content and frequency of particles colliding with the panel can be
measured.
[0012] While the above patents recognize the significant adverse
effects of debris colliding with active spacecraft, they do not
teach an effective solution for reducing the population of
threatening debris objects. Furthermore, these devices require
complex maneuvering and excessive use of propellant for their
maneuvering thrusters.
[0013] U.S. Pat. App. Pub. No. 2016/0023783 describes a spacecraft
control unit configured to guide and navigate an apparatus to a
target. The apparatus includes a dynamic object characterization
unit configured to characterize movement, and a capture feature, of
the target. The apparatus further includes a capture and release
unit configured to capture a target and deorbit or release the
target. A collection of these apparatuses is employed as multiple,
independent and individually operated vehicles launched from a
single launch vehicle for the purpose of disposing of multiple
debris objects. This patent application employs a very expensive
set of spacecraft that must maneuver to the targets. Excessive
propellant and maneuvering time are required for each target before
capture.
[0014] U.S. Pat. App. Pub. No. 2012/0068018 describes fiber-based
debris interceptors that are used to intercept and/or contain space
debris. The debris interceptors may be made up of fibers that are
formed in space from a material supply on a space vehicle. These
interceptors may be separated from the space vehicle and used to
passively drift in order to remove debris from an orbit or to
otherwise prevent debris from entering an orbit to avoid damaging a
satellite or other spacecraft traveling in that orbit. The debris
interceptors are not retrieved, but may be deployed prior to later
launches of valuable spacecraft in order to "cleanse" the intended
orbits of debris. Debris objects may pass through the debris
interceptor, but in so doing may lose energy so as to de-orbit.
This patent application describes a device that is used to protect
one satellite at a time.
[0015] In "Catchers' Mitt as an Alternative to Laser Space Debris
Mitigation," Phipps describes the placement of a single block of
low density material in an elliptical, near-equatorial orbit that
would sweep out debris in near-Earth space between about 400 km and
about 1100 km altitude. Phipps does not, however, address the
control of this block or the challenge of avoiding active
satellites. Nor does Phipps provide servicing or operating details
for the block.
[0016] In "Aerogels Materials as Space Debris Collectors," Woignier
discusses the use of very light weight materials for use in space
debris impact pads. Woignier does not, however, discuss the
vehicles on which such materials would be used.
[0017] Thus, previously proposed orbital debris removal approaches
require the use of extremely expensive and complex space systems in
order to accomplish the removal of single debris objects. The
implied complexity and expense of such approaches have prohibited
any actual debris removal missions.
BRIEF SUMMARY
[0018] Disclosed herein is an orbital debris interception vehicle,
including: a satellite bus; and a debris interception module
releasably coupled to the satellite bus, wherein the debris
interception module includes a debris impact pad. The debris impact
pad can include a Whipple shield, such as a pancake-shaped Whipple
shield.
[0019] According to aspects of the disclosure, the debris
interception module further includes a propulsion system and a
control unit configured to activate the propulsion system to
maneuver the debris interception module into an orbital pathway of
a debris object. Similarly, the control unit can be further
configured to activate the propulsion system to maneuver the debris
interception module out of an orbital pathway of an active
satellite, such as by reorienting the debris interception module to
present a minimum cross-section along a direction of the orbital
pathway of the active satellite.
[0020] To releasably secure the debris interception module to the
satellite bus, the satellite bus can include a docking probe, and
the debris interception module can include a receiver for the
docking probe.
[0021] Also disclosed herein is a method of intercepting orbital
debris, including the steps of: deploying at least one orbital
debris interception vehicle into an equatorial orbit, the at least
one orbital debris interception vehicle including: a satellite bus;
and a debris interception module releasably coupled to the
satellite bus, wherein the debris interception module includes a
debris impact pad; maneuvering the debris interception module such
that the debris impact pad of the debris interception module is in
an orbital pathway of a debris object; allowing the debris object
to impact the debris impact pad of the debris interception
module.
[0022] The method can also include releasing the debris
interception module from the satellite bus before the debris object
impacts the debris impact pad of the debris interception module;
and reconnecting the debris interception module to the satellite
bus after the debris object impacts the debris impact pad of the
debris interception module.
[0023] It is contemplated that the step of maneuvering the debris
interception module such that the debris impact pad of the debris
interception module is in an orbital pathway of a debris object can
include maneuvering the debris interception module into the orbital
pathway of the debris object after the debris interception module
is released from the satellite bus and before the debris object
impacts the debris impact pad of the debris interception
module.
[0024] Similarly, the method can include maneuvering the at least
one orbital debris interception vehicle such that it is out of an
orbital pathway of an active satellite, such as by reorienting the
at least one orbital debris interception vehicle to present a
minimum cross-section along a direction of the orbital pathway of
the active satellite. In aspects of the disclosure, this also
includes receiving tracking data for the orbital pathway of the
active satellite.
[0025] According to aspects of the disclosure, the step of
deploying at least one orbital debris interception vehicle into an
equatorial orbit includes deploying a plurality of orbital debris
interception vehicles into the equatorial orbit.
[0026] The step of maneuvering the at least one orbital debris
interception vehicle such that the debris impact pad of the debris
interception module is in an orbital pathway of a debris object can
include receiving tracking data for the orbital pathway of the
debris object.
[0027] The debris impact pad of the debris interception module can
include a Whipple shield.
[0028] The step of maneuvering the debris interception module such
that the debris impact pad of the debris interception module is in
an orbital pathway of a debris object can include maneuvering the
satellite bus with the debris interception module releasably
connected thereto.
[0029] The foregoing and other aspects, features, details,
utilities, and advantages of the present invention will be apparent
from reading the following description and claims, and from
reviewing the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0030] FIG. 1 is an illustration of the distribution of orbital
debris around the Earth.
[0031] FIG. 2 illustrates an exemplary debris field in which all
debris objects and active spacecraft are in polar orbits.
[0032] FIG. 3 depicts a debris interception vehicle according to
aspects of the instant disclosure.
[0033] FIG. 4 illustrates both a multi-layer Whipple shield and
two-layer debris shield.
[0034] FIG. 5 depicts the equatorial debris crossing band in which
debris interception vehicles can operate according to aspects
disclosed herein.
[0035] FIG. 6 is a representative operational flowchart according
to the teachings herein.
DETAILED DESCRIPTION
[0036] The instant disclosure provides apparatus and methods for
the systematic and sustained removal of orbital debris. The instant
disclosure also provides new orbital maneuvering techniques in
furtherance of the international mandate for space debris removal
and control.
[0037] In particular, described herein is an orbital debris
interception vehicle, including a satellite bus and a detachable
debris interception module ("DIM"). According to aspects of the
instant disclosure, the DIM can be placed in the direct path of a
debris object at the equatorial position and time of the debris
object's crossing.
[0038] The inventor estimates that the apparatus and methods
described herein will cost no more than about 1% of other possible
options for the cleanup and maintenance of the near-Earth
high-density debris field.
[0039] The following concepts provide relevant background to the
teachings herein: [0040] Every piece of orbital debris travels on a
unique and separate orbital path. Therefore, no two objects in
orbit have any interaction, except in those cases where a collision
takes place. [0041] Most debris objects are moving in circular or
near-circular orbits at speeds in excess of 7.25 km/s. [0042] All
Earth orbits are planar (i.e., in planes that contain the center of
the Earth). Thus, all objects that travel in highly inclined orbits
tend to intensify the density of objects as they fly over the polar
regions of the Earth. For this reason, it is theorized that a
higher frequency of collisions between debris and spacecraft, and
among debris objects themselves, occurs near the north- and
south-polar regions. A corollary is that the region of least debris
object density is the equatorial zone. [0043] LEO debris of most
concern to satellite operators resides in the altitude range of
about 600 km to about 1200 km and in orbits that are inclined at
least about 35 degrees to the equator. [0044] Every orbiting object
will cross the equator twice per circuit around the Earth, once
from north-to-south and once from south-to-north.
[0045] FIG. 1 is a depiction of the Earth 100 with the
instantaneous positioning of debris objects 110 from near-Earth to
beyond the geostationary Earth orbit ("GEO") 120 located at
approximately 35,800 km above the Earth and in the equatorial
plane.
[0046] FIG. 1 also depicts the two altitude limits of the most
dangerous LEO debris: the lower limit 130 at about 600 km altitude
and the upper limit 140 at about 1200 km altitude. Many pieces of
debris that threaten the safety of active scientific, commercial,
and military satellites in LEO are resident between these two
altitudes and must therefore pass between the depicted equatorial
circles 130, 140 twice each circuit around the Earth 100.
[0047] Thus, although FIG. 1 illustrates a much larger field of
orbital debris 110 about the Earth 100, the teachings herein will
be explained with reference to debris in LEOs between about 600 km
and 1200 km altitude (e.g., between limits 130 and 140). It should
be understood, however, that the instant disclosure can be extended
to the removal of orbital debris 110 at higher and/or lower
altitudes.
[0048] FIG. 2 illustrates several debris objects 110 and an
operating satellite 200 in high inclination orbits. As shown in
FIG. 2, debris objects 110 and satellite 200 are orbiting Earth 100
in polar orbits 150 having inclinations of about 90 degrees (as
those of ordinary skill in the art will appreciate, the
"inclination" of an orbit is the angle of the orbital plane as
measured from the equatorial plane). Although all orbits 150
depicted in FIG. 2 have the same inclination, no two orbits 150 are
in the same plane; that is, every orbit 150 crosses the equatorial
plane at different points.
[0049] Those of ordinary skill in the art will recognize that most
debris objects 110 are not in exact polar orbits 150, but are in
orbits 150 having inclinations greater than about 35 degrees. Thus,
the orbits 150 shown in FIG. 2 should be regarded as merely
illustrative for purposes of explaining an embodiment of the
present teachings, and in particular illustrative of the fact that
every debris object 110 and active satellite 200 travels in its own
orbit 150 and crosses the equatorial plane twice per circuit.
[0050] FIG. 3 depicts an orbital debris interception vehicle 240.
Orbital debris interception vehicle 240 includes a satellite bus
230 and a DIM 220.
[0051] Satellite bus 230 is similar to traditional satellite and/or
spacecraft buses in that it contains subsystems such as structure,
power, propulsion, telemetry, command, attitude determination and
control, and avionics. Satellite bus 230, which is not expendable,
provides support functions related to the control and operation of
orbital debris interception vehicle 240 for debris removal as
described herein. Those of ordinary skill in the art will be
familiar with satellite and/or spacecraft buses, such that a
detailed description of satellite bus 230 is not necessary
herein.
[0052] DIM 220, which is deployed and retrieved multiple times by
satellite bus 230, represents the working payload for orbital
debris interception vehicle 240. The function of DIM 220 is to
absorb debris object impacts, leaving the debris object with some
reduced level of orbital energy and/or altering the debris object's
orbital path in a manner that shortens the orbital life of the
debris object.
[0053] To the foregoing end, DIM 220 includes a debris impact pad
290. In general, debris impact pad 290 is constructed to deal with
debris objects of a particular size or size range. Moreover, DIM
220 is intended to withstand multiple debris encounters before it
requires replacement.
[0054] Therefore, it is contemplated that DIM 220, and more
particularly debris impact pad 290 thereof, can vary in size, mass,
and/or construction according to the type of debris object that DIM
220 is intended to encounter and/or the number of encounters it is
intended to absorb before replacement becomes necessary.
[0055] For example, according to aspects of the disclosure, debris
impact pad 290 can include a plurality of spaced layers of various
rigid and non-rigid materials, such as ceramic cloth, Kevlar
fabric, and aerogel, in configurations known as Whipple shields,
generally formed into pancake-like shapes. FIG. 4 depicts a
twin-layer Whipple shield 310, which can be used to intercept small
debris objects (e.g., debris objects of up to a few centimeters),
and a multi-layer Whipple shield 300, which can be used to
intercept larger debris objects. Those of ordinary skill in the art
will be familiar with the construction of Whipple shields,
including stuffed Whipple shields (e.g., Whipple shields that
include a filling, such as of ceramic cloth and Kevlar fabric,
between the bumpers), and thus will appreciate how to extend the
teachings herein to create Whipple shield impact pads 290 suitable
for even larger debris objects.
[0056] Of course, it is also contemplated that impact pad 290 can
take a form other than a Whipple shield without departing from the
scope of the instant disclosure. It is desirable, however, for
impact pad 290 to be generally pancake-shaped (that is, presenting
a large cross section in a first plane and a much smaller
cross-section in a second plane perpendicular to the first plane).
This allows impact pad 290 to be reoriented such that it presents
its maximum cross-section in the equatorial plane for a debris
encounter and its minimum cross-section in the equatorial plane to
avoid active satellites 200.
[0057] In embodiments, DIM 220 can also include an on-board
attitude determination and control system 250. System 250 can
utilize inputs from one or more sensors 280 and an onboard
propulsion system that includes thrusters 260 and propellant tanks
270 to maneuver DIM 220. For example, system 250 can be operable to
make corrections in position and/or speed of DIM 220, to maneuver
DIM 220 in order to make a timely crossing of orbit 150 of a debris
object 110, to damp any motion of DIM 220 after a debris encounter,
to maneuver DIM 220 out of the orbit 150 of an active satellite
200, to reorient DIM 220 such that it presents its minimum
cross-section along the direction of the orbit 150 of an active
satellite 200, to deorbit DIM 220 once expended, and the like.
[0058] DIM 220 can also include one or more cameras 285, which can
be utilized, for example, to assess the condition of DIM 220
following a debris encounter.
[0059] Satellite bus 230 and DIM 220 are releasably coupled to one
another. In embodiments of the disclosure, satellite bus 230
includes a docking probe 255, and DIM 220 includes a corresponding
receiver. This allows DIM 220 to separate from satellite bus 230
prior to a debris encounter, such that only DIM 220 intercepts the
debris object, keeping the non-expendable satellite bus 230 clear
of the debris. DIM 220 can then be reattached to satellite bus 230
after the debris encounter, such that satellite bus 230 can
maneuver DIM 220 to the projected location of a subsequent debris
encounter.
[0060] In use, at least one orbital debris interception vehicle 240
can be deployed into an equatorial orbit. For example, FIG. 5 shows
a plan view of the equatorial plane including debris objects 110,
active satellites 200, and a plurality of orbital debris
interception vehicles 240.
[0061] A DIM 220 can then be maneuvered such that its debris impact
pad 290 is in the orbit 150 of a debris object 110. For example, as
shown in the representative operational flow diagram of FIG. 6,
tracking data for debris objects 110 and active satellites 200 can
be provided by, inter alia, the United States Air Force, NASA,
commercial operators, and in-orbit sensors and input to a central
processing and scheduling unit, which can use the tracking data to
predict the times and locations at which debris objects 110 within
the 600 km to 1200 km altitude zone will cross the equatorial
plane. Debris interception vehicles 240 can also transmit telemetry
on their status and position to the central processing and
scheduling unit.
[0062] The central processing and scheduling unit can use the
received data (e.g., tracking data and debris interception vehicle
telemetry) to select debris objects 110 for intercept, to identify
the most suitable debris interception vehicle(s) 240 to make the
intercept (e.g., by identifying the most convenient, in terms of
minimum propellant expenditure, debris interception vehicle 240 to
the equatorial crossing point of the debris object 110 to be
intercepted), and to command the respective debris interception
vehicle 240 to move its associated DIM 220 into position (e.g.,
with its associated debris impact pad 290 making a timely crossing
of orbit 150 of the debris object 110 to be intercepted) and then
to release DIM 220 from satellite bus 230. Of course, system 250 of
DIM 220 can also be used to "fine tune" the position of DIM
220/debris impact pad 290 after release from satellite bus 230
pre-encounter.
[0063] Once positioned, debris object 110 can be allowed to strike
debris impact pad 290. Debris objects 110 can range in size from a
few millimeters to a few meters. Multiple small debris objects 110
can be removed in a single encounter with DIM 220. Larger debris
items 110 can break up as they pass through debris impact pad 290.
Generally, however, the encounter between debris object(s) 110 and
debris impact pad 290 will result in a loss of orbital energy for
debris object(s) 110, ultimately leading to atmospheric entry and
burn up. More particularly, depending on the amount of orbital
energy lost upon collision with debris impact pad 290, the debris
object 110 may: (1) enter a new orbit that will expose the debris
object 110 to increased atmospheric drag and an ultimate reentry;
(2) leave orbit immediately and reenter the Earth's atmosphere; or
(3) be absorbed (that is, captured) by debris impact pad 290.
[0064] Those of ordinary skill in the art will appreciate that
untracked debris objects 110 can also be intercepted, though such
intercepts will rely more on chance encounters than do intercepts
of tracked debris objects 110, which can be more readily predicted
from available tracking data.
[0065] Similarly, the central processing and scheduling unit can
command debris interception vehicles 240 to maneuver out of the
orbit 150 of an active satellite 200 as it crosses the equatorial
plane. For example, as discussed above, the central processing and
scheduling unit can reorient DIMs 220 to present its minimum
cross-section along the direction of the orbit 150 of an active
satellite 200.
[0066] Following the debris encounter, system 250 can be used to
damp any residual motion of DIM 220 and/or the condition of DIM 220
can be assessed (e.g., using camera(s) 285). Assuming that DIM 220
is not expended, it can be reconnected to its associate satellite
bus 230 and readied for its next debris encounter.
[0067] An additional result of a debris encounter may be a slight
orbit change for DIM 220. It is contemplated that these slight
orbit changes can be balanced over time, such as by alternating or
otherwise varying the direction of the debris encounter (e.g.,
balancing north-to-south intercepts with south-to-north
intercepts). If desired or required, additional corrections can be
made by system 250 on board DIM 220 and/or by satellite bus 230
when coupled to DIM 220.
[0068] According to aspects of the disclosure, debris interception
vehicle 240 is designed to be serviced by an On-Orbit Servicing
Unit ("OOSU"). For example, an OOSU can service and/or refuel the
propellant tanks on satellite bus 230 and/or DIM 220, and can also
deliver replacements for expended DIMs 220.
[0069] Although several embodiments have been described above with
a certain degree of particularity, those skilled in the art could
make numerous alterations to the disclosed embodiments without
departing from the spirit or scope of this invention.
[0070] For example, the teachings herein can be applied not only to
intercept orbital debris, but also to intercept any orbiting
device. This includes, without limitation, active but undesirable
orbiting devices, such as enemy spacecraft.
[0071] As another example, the teachings herein can be applied not
only in equatorial orbits, but also in near-equatorial orbits. For
purposes of this disclosure, the term "near-equatorial orbit" means
from equatorial orbit up to about 28.5 degrees inclination relative
to an equatorial orbit. Of course, the teachings could also be
applied at higher inclinations as well.
[0072] All directional references (e.g., upper, lower, upward,
downward, left, right, leftward, rightward, top, bottom, above,
below, vertical, horizontal, clockwise, and counterclockwise) are
only used for identification purposes to aid the reader's
understanding of the present invention, and do not create
limitations, particularly as to the position, orientation, or use
of the invention. Joinder references (e.g., attached, coupled,
connected, and the like) are to be construed broadly and may
include intermediate members between a connection of elements and
relative movement between elements. As such, joinder references do
not necessarily infer that two elements are directly connected and
in fixed relation to each other.
[0073] It is intended that all matter contained in the above
description or shown in the accompanying drawings shall be
interpreted as illustrative only and not limiting. Changes in
detail or structure may be made without departing from the spirit
of the invention as defined in the appended claims.
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