Crowded Space, a course of space debris and near Earth objects.
North Carolina State University
Osher Lifelong Learning Institute
Spring 2021 LLI-1-480
events, monitoring What we'll talk about Jan 25 Orbital Debris Orbital Mechanics 101, debris angers, notable events, monitoring Feb 1 Natural Objects How ISS pass apps work, Trojans, Asteroids, Comets & other NEOs Feb 8 What is being done now & in the future Space Law, cleanup & servicing missions Feb15 Wrap-Up & general astronomy Q&A
is more of a goal than "up" • Space isn't that far away (~100 miles) • Parabolas bad, ellipses good. • 17,500 mph magic number Orbital Mechanics 101: launch misunderstandings
are in orbit about the Sun, while most artificial debris are in orbit about the Earth. Hence, the latter are more commonly referred to as orbital debris. • Orbital debris is any man-made object in orbit about the Earth which no longer serves a useful function. • Non-functional spacecraft • Abandoned launch vehicle stages (rocket bodies) • Mission-related debris • Fragmentation debris (events) What is Orbital Debris? Office of Orbital Debris Management media briefing , 28 Apr 2009
Ford Needles (1961-1963) • 1966-04-30 Rio Brazil, Apollo SA-5 launched in 1964 • 1973—05-14 Skylab, mostly in Indian Ocean, sparsely populated are of western Australia • 1978-01-24 Cosmos 954 USSR Navy satellite small nuclear reactor over Canadian arctic • 1997-01-22 Delta2 debris hits woman in Turkey OK • 2001-01-21 Delta2 PAM-D reentry, motor casing Saudia Arabia, titanium pressure tank near Seguin TX, main prop tank near Georgetown TX • 2000-06-04 Compton Gamma Ray Observatory, intentionally deorbited into Pacific SE of Hawaii • 2001-03-23 Mir deorbit, ~1,500 fragments plunged into Pacific near Fiji. Taco Bell promotion • 2003-01-01 Columbia disaster spread debris process 28k sq mi across eastern TX / western LA, 80k+ pieces recovered • 2007 China destroys weather satellite, produces 900 bits of debris • 2008-02-20 USN shutdown of defunct spy satellite • 2009-10-01 Iridium 33 vs Cosmos 2251, 2,000 bits of debris • 2009 March ISS red conjunction • SpaceX StarLink Notable Events
NASA/SP-20205011318 Space Surveillance Network (SSN) tracking stations LSSC Lincoln Space Surveillance Center MSSS Maui Space Surveillance System AFSSSS Air Force Space Surveillance System
- 10 cm: disable or disrupt a mission Usually too small to track, too small to shield against • > 1 cm : Potentially catastrophic Conjunction assessments and collision avoidance manuevers Tracked by U.S. Space Surveillance Network Collision Risks
process for human spaceflight beginning with STS-26 in 1988. Initially based upon simple miss distance and a 4-km by 10-km by 4-km ellipsoid (football-shaped volume "keep-out" space around the Shuttle). • 1998 more sophisticated and higher fidelity conjunction assessment process for human spaceflight missions jointly developed by NASA & DoD Before launch of the first element of ISS • 2005 Similar process adopted selected robotic Earth Observation System satellites in LEO and TDRSS in GEO • 2007, extended the conjunction assessment process to all NASA maneuverable satellites within LEO and within 200 km of GEO. NASA Procedural Requirements 8715.6 Conjunction Assessment
101, debris angers, notable events, monitoring Feb 1 Natural Objects How ISS pass apps work, Trojans, Asteroids, Comets & other NEOs Feb 8 What is being done now & in the future Space Law, cleanup & servicing missions Feb15 Wrap-Up & general astronomy Q&A Feb 1 Natural Objects How ISS pass apps work, Trojans, Asteroids, Comets & other NEOs
Quadrantids (QUA) Dec 28-Jan 07 Jan 03 120 19 Lyrids (LYR) Apr 14-Apr 30 Apr 22 18 10 eta Aquarids (ETA) Apr 20-May 26 May 05 60 24 Southern delta Aquarids (SDA) Jul 17-Aug 12 Jul 30 20 21 Perseids (PER) Jul 22-Aug 23 Aug 12 100 4 Orionids (ORI) Oct 03-Nov 12 Oct 21 23 16 Leonids (LEO) Nov 03-Dec 02 Nov 18 15 14 Geminids (GEM) Nov 13-Dec 22 Dec 14 120 10 Ursids (URS) Dec 16-Dec 26 Dec 22 10 1 International Meteor Organization and Masahiro Koseki. ZHR = (cpen)/t C = % of sky obscured by clouds P = correction for light pollution (from limiting magnitude of 6.5) E = correction for elevation (from Zenith) N = number actually observed T = time in hours
(LYR) 18 eta Aquarids (ETA) 60 Southern delta Aquarids (SDA) 20 Perseids (PER) 100 Orionids (ORI) 23 Leonids (LEO) 15 Geminids (GEM) 120 Ursids (URS) 10 Images courtesy of Addison-Wesley ZHR = cpen/t C = % of sky obscured by clouds P = correction for light pollution (from limiting magnitude of 6.5) E = correction for elevation (from Zenith) N = number actually observed T = time in hours
of nearby planets into Earth's neighborhood. Comets: "dirty iceballs" Mostly ice, formed in outer solar system Asteroids: "icy dirtballs" Mostly rock, formed in warmer inner solar system NEA: Near Earth Asteroid PHA: Potentially Hazardous Asteroid
via a 1.5m telescope on Mt. Lemmon in Tucson, AZ Predicted to enter Earth's atmosphere the following day above Northdan Sudan at 0236Z, releasing energy equivalent 1 kiloton of TNT. Observed by Meteosat 8 & a KLM pilot over Chad Event Atmospheric Entry Airburst Detonation Altitude (km) 65.4 37 Observed Event Time (UT) 02:45:40 02:45:45 Predicted Event Time (UT) 02:45:38.45 02:45:45.13 Observed Long./Lat. (deg.) 31.4E. 20.9N 32.2E 20.8N Predicted Long./Lat. (deg.) 31.412E 20.933N 32.140E 20.793N Source: NASA/JPL CNEOS, METEOSAT
101, debris angers, notable events, monitoring Feb 1 Natural Objects How ISS pass apps work, Trojans, Asteroids, Comets & other NEOs Feb 8 What is being done now & in the future Space Law, cleanup & servicing missions Feb15 Wrap-Up & general astronomy Q&A Feb 8 What is being done now & in the future Space Law, cleanup & servicing missions
Hypervelocity MMOD impacts represent a substantial threat to spacecraft Rule of thumb: at 7km/s, aluminum sphere can penetrate completely through an aluminum plate 4x the sphere s diameter Damage from a 1.3cm diameter sphere at 7km/s Comparison of size of projectile to size of impact crater MMOD Risk Overview Eric Christiansen NASA/JSC July 2014
Hypervelocity MMOD impacts represent a substantial threat to spacecraft Rule of thumb: at 7km/s, aluminum sphere can penetrate completely through an aluminum plate 4x the sphere s diameter Damage from a 1.3cm diameter sphere at 7km/s Comparison of size of projectile to size of impact crater MMOD Risk Overview Eric Christiansen NASA/JSC July 2014
(SAW) EVA repair was caused by MMOD impact damage During STS-120 two solar array wings were removed from Z1 truss and relocated to P6 location. During re- deployment, the 4B solar array wing was torn in two places, due to a snagged guide wire. The guide wire was e ed a d c ff- added ab e e a a . MMOD Risk Overview Eric Christiansen NASA/JSC July 2014
ISS, differing by materials, standoff distance, and capability Heavier shields on front & sides (where we expect most MMOD impacts), less capable shielding on aft, nadir and visiting vehicles Earth velocity direction Russian Segment NASA JAXA ESA colors represent different MMOD shield configurations JAXA ISS Sheilding MMOD Risk Overview Eric Christiansen NASA/JSC July 2014 Several hundred MMOD shields protect ISS, differing by materials, standoff distance, and capability Heavier shields on front & sides (where we expect most MMOD impacts), less capable shielding on aft, nadir and visiting vehicles
Monolithic Brute force approach Whipple Developed by Fred Whipple in the 1940s. Sacrificial bumper to absorb energy, break projectile up Stuffed Whipple Layers of Nextel and Kevlar between bumper and spacecraft Multi-Shock Alternating layers of Nextel and Kevlar shock projective into harmless fragments
woven ceramic fabric (3M) Kevlar Also used in bulletproof vests (DuPont) Aluminum Heavy, but useful in front and back bumpers Mesh Steel or Aluminum, energy absorption, projectile break up
heat • Materials and their shapes Design for Demise • Optimize heat transfer to encourage early break-up • Orifices, lattice structures • Minimize blast radius • Keep fragments together ESA CleanSpace webinar on Design for Demise
Most are tumbling uncontrollably • Speed and direction cannot be determined until you get close • Then you must: • sync the debris removal spacecraft with the tumbling debris • Get close enough to capture .... • Without crashing Active Debris Removal is Hard
events, monitoring Feb 1 Natural Objects How ISS pass apps work, Trojans, Asteroids, Comets & other NEOs Feb15 Wrap-Up & general astronomy Q&A Feb15 Wrap-Up & general astronomy Q&A Feb 8 What is being done now & in the future Space Law, cleanup & servicing missions What we'll talk about
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