asteroidsquads/issb – a synergetic neo deflection campaign ... · iaa sg35finalreport.pdf neas Ø...
TRANSCRIPT
Folie 1AsteroidSQUADS > jtg RY-OR HB > PlanDefCon2011 > 11 MAY 2011 09:10
2011 IAA Planetary Defense Conference – From Threat to Action
ASTEROIDSQUADS/iSSB – a Synergetic NEO Deflection Campaign and
Mitigation Effects Test Mission Scenario
J.T. Grundmann@, S. Mottola, M. Drentschew*, M. Drobczyk, R. Findlay, M. Hallmann, A. Heidecker, R. Kahle, E. Kheiri, A. Koch, V. Maiwald, O. Mierheim, F. Nohka,
D. Quantius, M. Siemer, P. Zabel, T. van Zoest
DLR German Aerospace Center* ZFT Zentrum für Telematik
Folie 2AsteroidSQUADS > jtg RY-OR HB > PlanDefCon2011 > 11 MAY 2011 09:10
Origins in the rearview mirror…
1st IAA Planetary Defense Conference White Paper recommendations:
live test of asteroid deflection methodsstudy momentum transfer (particularly kinetic interceptor)
„Fund research and conduct flight experiments to characterize and refine the effectiveness of Kinetic Impact as a deflection technique.”
exercise and test existing space and civil defence infrastructure develop response protocols & international participation
„Future conferences should encourage the development of deflection campaigns […]. The campaign design should specify the campaign and mission timelines, launch vehicle(s) and spacecraft, deflection option(s), and resource requirements for such an effort.”
overall focus of 2009: sub- & small PHOs (20 m < Ø < 500 m)
Folie 3AsteroidSQUADS > jtg RY-OR HB > PlanDefCon2011 > 11 MAY 2011 09:10
…from the memorable quotes department...
„Almost all victims are caused by km-size NEOs but the Tunguska type we are most likely to see.“
„The risk of surprise by a large impact has been almost completely retired.“
„The risk of impact has not changed by doing asteroid surveys alone.“
„At a point in time you just will have to go out to one there and just hit it with something.“
„The one thing we must not be afraid of is to look stupid on camera.“
Folie 4AsteroidSQUADS > jtg RY-OR HB > PlanDefCon2011 > 11 MAY 2011 09:10
…and the devil in the details.*
images: l.: Gustave Doré, r.: Cervantes, ©1605,inset Dan Durda* lyrics: The Walkabouts
even dedicated scientific NEA missions are notoriously hard to sell
long interplanetary flight time to rendezvous with target
visually least attractive, most unspectacular targets
technology limits payload to object of interest
science yield tied to new technology
size down, risk up…
* …you are as brave as you believe - you are as brave as what you won't repeat … the future is a slow retreat - the future is a muscle you don't have…
Folie 5AsteroidSQUADS > jtg RY-OR HB > PlanDefCon2011 > 11 MAY 2011 09:10
AASTEROIDSTEROIDSQUADS/iSSBSQUADS/iSSB
…or how to solveone problem
by adding5 more :
images: special effects screenshots from Raumpatrouille Orion – Ep.2 – Planet außer Kurs, Sat.01.Oct.1966, Bavaria Filmstudios
Folie 6AsteroidSQUADS > jtg RY-OR HB > PlanDefCon2011 > 11 MAY 2011 09:10
notnotΘΘworkworkHeavy Launcher Development
testing is very expensivebillion dollar comsat passengers routinely taken for test flights~3 non-perfect flights in the first 10 typical before steady commercial-grade performance achievedresulting low cadence in first crucial marketing phase
Space Debris‚realistic‘ GTO/GEO launch vehicle tests litter space with big targets inviting local Kessler cascade big dead lead-sats placed close to most sensitive orbit (CoC-compliant or not…)
Planetary Science ‚big‘ science just too Cluster‘d to fly on new launch vehicles ‚small‘ NEO mission funding hard to get past the windmills
Planetary / Civil Defencedeflection campaigns: paper exercisesmulti-spacecraft operations: terra incognitaon-target performance: unknown
Concerned Politicsplanetary defence tests seen as the thin end of a very expensive & risky standing defence wedgeweaponization risk – the target of deflection may as well be on Earthtechnology dual use potential e.g. for covert missile defence testingperceived as preparatory to non-conventional high energy options
Cognitive Bias but km-class NEOs are the real killers, they said but not in my lifetime but Bruce Willis solved that, didn‘t he?but we don‘t have a chance
Folie 7AsteroidSQUADS > jtg RY-OR HB > PlanDefCon2011 > 11 MAY 2011 09:10
networkHeavy Launcher Development
proper ‚Heavy‘ testing with GTO or GEO-like burn profilemid-range payload stack mass from small net payload massslightly less than perfect performance may be tolerablelead-free real payload to prove launcher capabilities ‚all-up‘multiple-payload capabilities demonstration easily fitted in
Space Debrislow space debris generation risk trajectory possiblenon-standard orbits for all separated itemspayload stack most likely escapes or re-enters no CoC out there…
Planetary Sciencefast mission scenarioquite a bit of ‚pure‘ science potential beyond immediate deflection-related contextlow-cost set of instrumentsinstrument mix possiblebreak the one-mission-per-career-life routine
terms and conditions apply
Concerned Politicsindependently observable by amateur astronomers and professional science communityimpactor too small to include anything but ist own masscamera payload similar to interplanetary probessmall, low-cost, serialized production spacecraftcloser to commercial than ‚hardened‘ technologies
Cognitive Biasputs focus on most frequent NEO impact event class with a significant risk attacheddemonstrates concepts and capabilities in a practical and visible way
Planetary / Civil Defencedeflection campaigns: realistic global exercises!multi-spacecraft operations: practice possible!on-target performance: space spectacular!
background image: NASA
Folie 8AsteroidSQUADS > jtg RY-OR HB > PlanDefCon2011 > 11 MAY 2011 09:10
6 1 synthesis as a campaign & mission timeline
small & smart interceptor spacecraft and mission-specific launcher hardware produced well in time for first flight test of a new or upgraded heavy launcher
launcher test schedule triggers search for suitable target ( ~3..6 months to launch)complete flight time ≤ 3 months (launch to final damage assessment photo opportunity)target selection from networked operating surveys, with NEA catalogues as back-upwithin launch site trajectory constraints for GTO/GEO-like ascent profilestill in the night sky when hit, for ground-based observationswithin radar range before & after impacts (Goldstone at least)
shoot at what‘s delivered by nature (play the real thing - within above constraints)focus on deflection test and ground ops exercises, no science-driven target selectionelement of chance welcome! (orbit parameters, encounter Δv, target composition)
hot interceptor relays final death plunge telemetry to next inbound interceptor for store-forward transmission to Earth at lower rate, via high-gain antenna
video: up to 1000 frames/sec 1 frame per m per km/s encounter-Δv (~17 km/s avg.)on-board automatics tests possible (e.g. pre-set ‚special event timer‘ by telemetry ping)
Folie 9AsteroidSQUADS > jtg RY-OR HB > PlanDefCon2011 > 11 MAY 2011 09:10
vital statistics at a glance…
every month, ~8…20 known NEOs approach Earth to within 0.2 AU ≈ 78 Lunar Distances (LD)
listings are published by the MPC *
1.6 km1757.5 LDJun 12002 JC
2.5 km16.165.3 LDMay 52003 YT1
1.2 km17.975.5 LDMay 52008 FU6
23 m26.48.6 LDMay 22009 UK20
10 m28.28.9 LDApr 272008 UC202
2.2 km16.462.5 LDApr 152002 DB4
2.6 km16.145.5 LDMar 102000 PN9
1.8 km1767.7 LDFeb 202003 YG118
15 m27.39.3 LDJan 302011 BF10
62 m24.12.2 LDJan 262011 AL37
39 m25.48.3 LDJan 202011 BW10
18 m27.00.9 LDJan 202011 BY10
29 m25.99.5 LDJan 192011 AB37
9 m28.50.8 LDJan 172011 AN52
SizeMag.Miss DistanceDate(UT)Asteroid
extracts are carried by many sites, e.g. spaceweather.com, here as of 26 JAN 2011
a similar number of mostly small NEOs is discovered every month
mostly discovered a few days before closest approachmostly much closer to Earthmostly „Tunguska-sized“
PHO surveys getting into gear now * http://www.cfa.harvard.edu/iau/lists/CloseAppLong.html
Folie 10AsteroidSQUADS > jtg RY-OR HB > PlanDefCon2011 > 11 MAY 2011 09:10
…on the edge between dimple and bump
graphs: adapted excerpts of A.W. Harris (U.S.) via I. Bekey, IAA sg35finalreport.pdf
NEAs Ø > ~20 mcan cause massive low-altitude airbursts at the ≥1 Mt-TNT levelbegin to penetrate the shielding provided by the atmosphere
NEAs ~50 m < Ø < 1 kmcarry the second, regional component of lethal risk are in the focus of the new survey goals @ Ø > ~140 m
NEAs Ø < 700 mcover the range of the sub-power-law population‚bends‘ in the population curve may mark transitions between different regimes of NEA structure and/or composition
NEAs ~50 m < Ø < ~300 m
100 m / 100 Mt / 100 centuries class – 1 % likelihood per century
upper end of „Tunguskoids“ – lower end of PHO size definitions
covers crest of the ‚shallow bump‘ of lethal risk
Folie 11AsteroidSQUADS > jtg RY-OR HB > PlanDefCon2011 > 11 MAY 2011 09:10
instruments
Ranger-like camera bankcommercial photo & amateur astronomy optics adapted
short mission - low total radiation dose!
narrow, medium & wide-angle cameras (NAC, MAC, WAC)main drivers:
guidance at a wide range of distances throughout the mission, last-millisecond close-up surface photography, remote observation of impact ejecta coma
NAC: typical planetary 1K² conventional FT-CCD (or EMCCD for marginal optics), ~1.5° Field of View, ~10...17 fps, panchromatic, at least 2 cameras parallel
MAC: 512² or TV format (PAL / NTSC EMCCD available), ~5° FoV, ~50...72 fpsWAC: ultra-fast kpixel@kframes sensor (e.g. 128² AO EMCCD), ~15° FoV, ~1 kfps
common max. pixel clock of 18…20 MHz & moderate A/D resolution and/or look-up table compression of brightness from ≤ 12 bit A/Dif any, fixed strip filters for taxonomy, possibly also TV-style colourno filter wheels, but e.g. multiple WAC camera heads & rolling read-outstill ≥ 100 Mbps at full speed on each camera / sensor type, per channel
background image: NASA
Folie 12AsteroidSQUADS > jtg RY-OR HB > PlanDefCon2011 > 11 MAY 2011 09:10
yet more instruments?
maybe dust countersemphasis on size-frequency counting likely due to unknown contamination of ejectadust composition analyzers only if thought feasible due to differential analysis
different types of impactors, e.g. bare vs SYLDA- or upper-stage-sheperding spacecraftembedded tracer compounds in impactors, e.g. non-toxic, non-radioactive exotic elements expected to be rare in target
maybe plasma instruments: the usual suspects…?volatiles: interstitial, impact-generated, impactor contamination, solar wind interactiondifferences in natural and artificial coma properties
definitely: more instruments displace cameras not required for guidance
background image: NASA
Folie 13AsteroidSQUADS > jtg RY-OR HB > PlanDefCon2011 > 11 MAY 2011 09:10
ASTEROIDFINDER & other ‚Kompaktsatellit‘ baselines
BIRD TET (/SSB) (/SSB)22. Oct. 2001 launch this year secndary payload (‚piggy-back‘) launch dedicated launch620 · 620 · 550 mm³ 880 · 620 · 550 mm³ 1000 · 800 · 800 mm³ 2120 · 1000 · 800 mm³92 kg 120 kg 150 kg 138 kg
DLR-internal competition for first ‚Kompaktsatellit‘ science payload in 2008requirement of heritage re-use based on TET spacecraft & payload mass, power & volumerequirement for payload pushing technical limits
ASTEROIDFINDER:1st iteration: TET envelope + deployable sunshield + 45° solar panel
2nd iteration: TET-driven smallest common denominator ‚piggy-back‘ box3rd iteration: dedicated launch & eliminate deployable sunshield
propagation to other studies, e.g. Carbonsat-C, Carbonmon, AHAB,…
ASTEROIDSQUADS
135 kg
Folie 14AsteroidSQUADS > jtg RY-OR HB > PlanDefCon2011 > 11 MAY 2011 09:10
never a „Standard-…“ in the CEF –the ‚Kompaktsatellit‘ way of design
the out-of-the-drawer bus kit – a menu of options on unit level and subsystem leveloptions of dissimilar maturity can be combined in similar system due to well known interfacesstarting point in this study: the last state of the ‚piggy-back‘ „AsteroidFinder/SSB“ baselineevolution of a payload-requirements-driven bus solution in ~1 Concurrent Engineering weekfeasibility study in ~3 weeks with extensive Concurrent Engineering methods (& facility) use
the suffix »/SSB« originally »/StandardSatellitenBausatz« ≈ ≈ the »same-ol, same-ol kit« , not a »/StandardSatelliteBus«
BIRDTET
AsteroidFinderCHARM
flight-provenspace qualified
developedbreadboarded
designedstudied
LiveSat
structure
maturity
BIRDTET
AsteroidFinderCarbonMonmore CEFs…
C&DH BIRDTET
power
AsteroidFinder
BIRDTET
comms
AsteroidFinder
BIRDTET
wheels
BIRDTET
AsteroidFinder
battery
BIRDTET
gyros
AsteroidFinder
X antennaAsteroidFinder
BIRDcoarse sun s.
BIRDS antenna
BIRD
TET
GPS
PROBA-2 commercialcommercial
Phase BPhase APhase 0
CEF
[Payload]/BIRD[Payload]/TET[Payload]/SSB
[Payload]-C[ompact]subsystem reuse
naming the options: [Payload]/[Platform]
unit reusecomponent reuse
AsteroidFinder
CarbonSat-C
Folie 15AsteroidSQUADS > jtg RY-OR HB > PlanDefCon2011 > 11 MAY 2011 09:10
Ka-bandantenna
X-bandantenna
CFK Plate with MLI
Front EndElectronic
InterconnectionModule
Solar array
MLI Cover
High ResolutionCamera
Middle RangeCamera
Webcam
Propulsion
Bus
Cold Radiator
the kit
Folie 16AsteroidSQUADS > jtg RY-OR HB > PlanDefCon2011 > 11 MAY 2011 09:10
Interceptor Configuration
50 degreeSunshield
Propulsion (8 x 1N thrusters, 1x 400N thruster)
ACS
1 x Ka-band antenna 2 x X-band antenna 4 x Interlink antenna
Communication
2 x High Resolution Cameras4 x Middle Range Camera4 x Webcam
Payload
179kgMass
1m x 0,78m x 0,7mDimension
1m
0,78m
0,7m
+ a few negotiable protrusions
incl. 35 kg instruments& 25 kg propellant
Folie 17AsteroidSQUADS > jtg RY-OR HB > PlanDefCon2011 > 11 MAY 2011 09:10
0
200
400
600
800
1000
1200
0 2 4 6 8 10v, km/s
h, k
m
GTO AsteroidSQUADS
‚heavy‘ launcher performance model
dated but off-the-shelf available parametric study project performance model of a moderately upgraded Ariane 5 configuration
selected from a set of models by matching GTO performance with reasonable extrapolations of market requirements for the present decade
~12 t payload mass to GTO1..4 comsats delivered per launch to GTOGTO launch window ~22:20…23:20 UTC
upgraded cryogenic upper stage + mild tuning of core stage and booster
model combined with flown payload stack structures and fairingsshort fairingSYLDA dual launch structureSPELTRA triple / multiple launch structureASAP-5 auxiliary payloads carrier platform structure
ASAP – Ariane Structure for Auxiliary PayloadsSPELTRA – Structure Porteuse Externe pour Lancements Triple Ariane
(now: … pour Lancements Multiples)SYLDA – SYstème de Lancement Double Ariane
Folie 18AsteroidSQUADS > jtg RY-OR HB > PlanDefCon2011 > 11 MAY 2011 09:10
0
200
400
600
800
1000
1200
0 200 400 600 800 1000 1200t, s
h, k
m
GTO AsteroidSQUADS
‚heavy‘ launcher escape performance
payload mass off-loading to exceed escape velocity safelyapply GTO burn sequence as for maximum payload to GTOescape velocity design goal:
impact at ~0.05 AU from Earth – maximum PHO Emoidv∞ ~ 1 km/s – reasonably safe launcher performance margin
acceptable design range:~450 m/s < v∞ < ~3.8 km/s after 90 days:
out of Earth-Moon zone of influenceimpacts at < 0.2 AU – MPC long fly-by list limit
baseline performance of selected launcher model: 2 payload blocks can be delivered to interplanetary space
v∞,2 = 3060 m/shigh but still acceptable
3 payload blocks can not escape the Earth-Moon systemQ3 ≈ 130000 km
partial block off-loading unlikely to achieve minimum escape conditions
Folie 19AsteroidSQUADS > jtg RY-OR HB > PlanDefCon2011 > 11 MAY 2011 09:10
6,71
m
4m
4,57m
12,4
4m
1 interceptor with comsat cone (medium impactor)
8 interceptors on ASAP ring underfairing (baseline impactor)
1 interceptor attached to SYLDA shell under comsat cone (heavy impactor)
1 interceptor with comsat cone
8 interceptors on ASAP ring underSYLDA
1 interceptor attached to upper stageunder comsat cone
Launcher Configuration:20 impactors – 2 medium – 2 heavy
ASAP – Ariane Structure for Auxiliary PayloadsSPELTRA – Structure Porteuse Externe pour Lancements Triple Ariane
(now: … pour Lancements Multiples)SYLDA – SYstème de Lancement Double Ariane
Folie 20AsteroidSQUADS > jtg RY-OR HB > PlanDefCon2011 > 11 MAY 2011 09:10
idea: do S-L 9 sub-PHO @ 10‘s of LD
ASTEROIDSQUADS/iSSB:Serendipitous Quantitative Understanding and
Assessment of Deflection Strategiesusing the DLR Kompaktsatellit bus kit evolved
and improved for interplanetary flight
not to scale
note: there ain‘t no such thing as a free launch. (payload not including space debris)
images: t.: NASA, b.: geosmile.de
Folie 21AsteroidSQUADS > jtg RY-OR HB > PlanDefCon2011 > 11 MAY 2011 09:10
flotilla impact sequences – close pair Ø 140 mΔv = 17 km/s
Δs = 26000 kmΔt = 25 min100 Mbps
s = 5500 kmΔt = 5.5 min
Δs = 250000 kmΔt = 4 h5 Mbps
Δs ~ 26000 kmΔt ~ 25 min
5 Mbps
Δs ~ 0.05 ≤ 0.2 AU~3 Mbps
NAC NAC NAC NAC NAC NACMAC
MAC
MAC
MAC
MAC
MAC
MAC
MACWW
WW
WW
WW
WW
WW
WW
WW
WW
WW
WW
WW
WW
WW
WW
WW
WWWW
NACNEA ≥ 1 pixel:s = 5500 kmT - 5.5 min1024² pixel
17 fps
NACNEA full frame:
s = 5.5 kmT - 0.32 s
1024² pixel17 fps
MACNEA full frame:
s = 1.6 kmT - 0.094 s512² pixel
48 fps
WACNEA full frame:
s = 0.5 kmT - 0.031 s128² pixel966 fps
WA
C: 30 fram
es to impact
NEA ≥ 1 pixel:s = 68 km
T - 4 sNEA ≥ 1 pixel:
s = 820 kmT - 48 s
Δt ≤ 90 d
Folie 22AsteroidSQUADS > jtg RY-OR HB > PlanDefCon2011 > 11 MAY 2011 09:10
flotilla impact sequences – single impactor Ø 140 mΔv = 17 km/s
s = 5500 kmΔt = 5.5 min
Δs = 250000 kmΔt = 4 h5 Mbps
Δs ~ 26000 kmΔt ~ 25 min
5 Mbps
Δs ~ 0.05 ≤ 0.2 AU~3 Mbps
NAC NACMAC
MAC
W
W
WW W
NACNEA ≥ 1 pixel:s = 5500 kmT - 5.5 min1024² pixel
< 1 fps
NACNEA full frame:
s = 5.5 kmT - 0.32 s
1024² pixel< 1 fps
MACNEA full frame:
s = 1.6 kmT - 0.094 s512² pixel~ 2.4 fps
WACNEA full frame:
s = 0.5 kmT - 0.031 s128² pixel~48 fps
WA
C: ~1±1 fram
es to impact
NEA ≥ 1 pixel:s = 68 km
T - 4 sNEA ≥ 1 pixel:
s = 820 kmT - 48 s
Δs ~ 26000 kmΔt ~ 25 min
5 Mbps
Folie 23AsteroidSQUADS > jtg RY-OR HB > PlanDefCon2011 > 11 MAY 2011 09:10
6,71
m
4m
4,57m
11,5
m15
,5m
outlook & future work:more serious launchers, more serious targets
Apophisto Earth
1999RQ36 to Earth
Toutatisto Earth
1950DA to Earth
AsteroidSQUADS to Toutatis
AsteroidSQUADS to 1999RQ36
AsteroidSQUADS to Apophis
AsteroidSQUADS to 1950DA
Launch Epoch (UTC)
Rel
ativ
e D
ista
nce
(km
)
Conjunctions between AsteroidSQUADS and Asteroids Depending on Launch Date (Transfer Time up to 500 Days)
Folie 24AsteroidSQUADS > jtg RY-OR HB > PlanDefCon2011 > 11 MAY 2011 09:10
Conclusions
the combination of a heavy launch vehicle test flight with a useful planetary defence methods test and infrastructure exercise is feasible
the effort to set up the space segment using multiple small spacecraft with largely identical configurations is estimated to be comparable to a medium-class mission, but a career lifetime of science work is not at risk
re-flight in case of launcher failure is technically not difficult due to the series production infrastructure previously set up for the first attempt
a high risk of failures and performance below the envisaged level is not just accepted, but taken as a chance to learn in time and with time
the expenses can be shared by all parties participating in the campaign by paying for their own activities conducted under the common scenario
Folie 25AsteroidSQUADS > jtg RY-OR HB > PlanDefCon2011 > 11 MAY 2011 09:10
Questions?
Who knows whether, when a comet shall approach this globe to
destroy it, as it often has been and will be destroyed, men will
not tear rocks from their foundations by means of steam,
and hurl mountains, as the giants are said to have done,
against the flaming mass? - And then we shall have traditions of Titans again, and of wars with
Heaven.
Lord Byron, 1822
images: l.: via wikipedia 2008, r.: geosmile.de
Folie 26AsteroidSQUADS > jtg RY-OR HB > PlanDefCon2011 > 11 MAY 2011 09:10
back-up slides
bus accommodation detailssolo impactor mass budget40 impactor stack details500 day encounters enlargedorbit plot Earth & Moon – ASTEROIDSQUADS – Apophis
Folie 27AsteroidSQUADS > jtg RY-OR HB > PlanDefCon2011 > 11 MAY 2011 09:10
1N Thruster
400N Thruster
Propellant Tank (6l)
HeliumTank (0,7l)
Sun sensor
X-bandTrans/Rec
X-bandTransponder
PayloadDPU
Battery
PowerBoards
C&DH
Ka-bandTrans/Rec
InterlinkTrans Gyro
Interlink antenna
Folie 28AsteroidSQUADS > jtg RY-OR HB > PlanDefCon2011 > 11 MAY 2011 09:10
Mass Budget
1,5 kgLauncher I/F
179 kgOverall
20 kgHarness
9 kgThermal
1 kgACS
17 kgPower
10 kgC&DH + DPU
35 kgPayload
17,5 kgCommunication
25 kgPropellant
26 kgPropulsion
17 kgStructure
Communication10%
Structure9%
ACS1%
Propulsion15%
Propellant14%
Thermal5%
Payload19%
C&DH + DPU 6%
Power9%
Launcher1% Harness
11%
Folie 29AsteroidSQUADS > jtg RY-OR HB > PlanDefCon2011 > 11 MAY 2011 09:10
6,71
m
4m
4,57m
11,5
m15
,5m 1 interceptor with comsat cone
8 interceptors on ASAP ring underfairing
1 interceptor attached to SYLDA shellunder comsat cone
1 interceptor with comsat cone
8 interceptors on ASAP ring underSYLDA
1 interceptor attached to SPELTRA shell or upper stage under comsat cone
outlook:upgraded launcher configuration with ASAP
ASAP – Ariane Structure for Auxiliary PayloadsSPELTRA – Structure Porteuse Externe pour Lancements Triple Ariane
(now: … pour Lancements Multiples)SYLDA – SYstème de Lancement Double Ariane
Folie 30AsteroidSQUADS > jtg RY-OR HB > PlanDefCon2011 > 11 MAY 2011 09:10
Rel
ativ
e D
ista
nce
(km
)Conjunctions between AsteroidSQUADS follow-on and Asteroids Depending on Launch Date ( Transfer Time up to 500 d )
1950DA to Earth
Apophisto Earth
1999RQ36 to Earth
Toutatisto Earth
AsteroidSQUADS to Toutatis
AsteroidSQUADS to 1999RQ36
AsteroidSQUADS to Apophis
AsteroidSQUADS to 1950DA
Launch Epoch (UTC)
Assumptions: Ariane 5 study model, GTO launch window ~22:20-23:20 UTC, inertial velocity after launch: 10.7703 km/s v_infinity: 3.06 km/s; 20 impactor stack; no mid course manoeuvre; Transfer duration up to 500 days allowed approaches of ~ 1 Gm (0.0067 AU) relative distance reached
Folie 31AsteroidSQUADS > jtg RY-OR HB > PlanDefCon2011 > 11 MAY 2011 09:10