Editing Deep Space 2

{{Short description|Failed NASA impactor mission to Mars (1999)}}
{{Infobox spaceflight
| name                  = Deep Space 2

<!--image of the spacecraft/mission-->
| image                 = [[File:DS-2 probes with mounting.jpg|290px]]
| image_caption         = A ''Deep Space 2'' probe with heatshield and mounting attached to the ''[[Mars Polar Lander]]''
| image_size            = 300px

<!--Basic details-->
| mission_type          = [[Mars]] impactor
| operator              = [[NASA]]{{\}}[[JPL]]
| website               = [https://www.jpl.nasa.gov/nmp/ds2/facts/facts.php jpl.nasa.gov]
| mission_duration      = {{time interval|3 Jan 1999|3 Dec 1999|show=dhm}}<br><small>Mission failure</small>

<!--Spacecraft properties-->
| manufacturer          = [[Jet Propulsion Laboratory]]
| launch_mass           = {{cvt|2.4|kg|lb|abbr=on}} each
| power                 = 300mW [[Lithium battery|Li-SOCl2 batteries]]
<!-- Batteries = 2 x 600 [[mAh]] [[Lithium battery|Lithium-Thionyl Chloride]] (Li-SOCl2) -->
<!-- suggestion to move more detailed information about batteries into main text body -->

<!--Launch details-->
| launch_date           = {{start date|1999|01|03|20|21|10|7=Z}}
| launch_rocket         = [[Delta II]] 7425-9.5<br>D-265
| launch_site           = [[Cape Canaveral Space Force Station|Cape Canaveral]] [[Cape Canaveral Air Force Station Space Launch Complex 17|SLC-17]]
| launch_contractor     = [[Boeing]]
| deployment_from       = [[Mars Polar Lander]] (precluded)

<!--end of mission-->
| disposal_type         = Failure in transit
| last_contact          = {{end date|1999|12|03|20|00|7=Z}}<ref name="dates" />

<!--
    The following template should be used for ONE of the three above fields "end_of_mission", "decay" or "landing" if the spacecraft is no longer operational.
    If it landed intact, use it for the landing time, otherwise for the date it ceased operations, or the decay date if it was still operational when it re-entered.
    {{end date|YYYY|MM|DD|hh|mm|ss|TZ=Z}} (for Zulu/UTC) or {{end date|YYYY|MM|DD}} (if time unknown) 
-->

|interplanetary         = <!--Infobox spaceflight/IP can be called multiple times for missions with multiple targets or combined orbiter/lander missions, etc-->
 {{Infobox spaceflight/IP
   |type                = impactor
   |object              = [[Mars]]
   |component           = ''Amundsen'' and ''Scott''
   |arrival_date        = ~20:15 UTC [[Spacecraft Event Time#SCET versus Earth time|ERT]], December 3, 1999
   |departure_date      = <!--Date of leaving orbit for orbiters, date of launch for landers which took off again-->
   |location            = {{Coord|73|S|210|W|globe:Mars|name=Deep Space 2}} (projected) 
}}


<!--Only use where a spacecraft/mission is part of a clear programme of sequential missions. 
If in doubt, leave it out-->
| programme             = '''[[New Millennium program]]'''
| previous_mission      = [[Deep Space 1]]
| next_mission          = [[Earth Observing-1]]
| programme2            = '''[[Mars Surveyor '98]]'''

<!--mission insignia or patch-->
| insignia              = [[File:M98patch.png|180px]]
| insignia_caption      = ''Mars Surveyor 98'' mission logo
| insignia_alt          = <!--image alt text-->
| insignia_size         = <!--include px/em; defaults to 180px-->

|instruments_list=
 {{Infobox spaceflight/Instruments
  |name1=[[accelerometer|Impact accelerometer]]
  |name2=Water detection apparatus
  |name3=Soil conductivity probe
  |name4=Descent accelerometer
 }}
}}
'''Deep Space 2''' was a [[NASA]] [[space probe]], part of the [[New Millennium Program]]. It included two highly advanced miniature [[space probe]]s that were sent to [[Mars]] aboard the [[Mars Polar Lander]] in January 1999.<ref name="dates">{{Cite web|first1=Phil|last1=Davis|first2=Kirk|last2=Munsell|title=Missions to Mars: Deep Space 2 - Key Dates|url=http://solarsystem.nasa.gov/missions/profile.cfm?Sort=Target&Target=Mars&MCode=DS2|work=Solar System Exploration|publisher=NASA|date=January 23, 2009|access-date=July 8, 2009|archive-url=https://web.archive.org/web/20090420132023/http://solarsystem.nasa.gov/missions/profile.cfm?Sort=Target&Target=Mars&MCode=DS2|archive-date=April 20, 2009|url-status=dead}}</ref> The probes were named "Scott" and "Amundsen", in honor of [[Robert Falcon Scott]] and [[Roald Amundsen]], the first explorers to reach the Earth's South Pole. Intended to be the first spacecraft to penetrate below the surface of another planet, after entering the Mars atmosphere DS2 was to detach from the Mars Polar Lander mother ship and plummet to the surface using only an [[aeroshell]] [[Impactor (spacecraft)|impactor]], with no [[parachute]]. The mission was declared a failure on March 13, 2000, after all attempts to reestablish communications following the descent went unanswered.<ref name="NSSDC">{{Cite web|title=Deep Space 2 (DEEPSP2)|url=https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=DEEPSP2|work=NSSDC Master Catalog|publisher=NASA - National Space Science Data Center|year=2000|access-date=July 8, 2009}}</ref>

The Deep Space 2 development costs were US$28 million.<ref name="AP-mission-costs">{{cite news |url= https://apnews.com/article/0520e4b6fa628215ee93b0d3c74d6ce2A |title= Mars Polar Lander Mission Costs |publisher= The Associated Press |date= 1999-12-08 |access-date=2020-09-30}}</ref>

== Overview ==
[[file:Deep Space 2 project manager, Sarah Gavit Sarahwprobe-1.jpg|thumbnail|Deep Space 2 project manager Sarah Gavit with the engineering hardware of the probe]]

Deep Space 2, also known as "Mars Microprobe,"<ref name="NSSDC" /> was the second spacecraft developed under the NASA New Millennium Program to flight-test advanced technologies concepts for space missions. The purpose of the program was to do high-risk technology demonstration, with a motto "Taking risks to reduce future danger."<ref>{{cite news |first=Nola Taylor |last=Redd |url=https://www.space.com/new-millennium-program.html |title=NASA's New Millennium Program: Taking Risks to Reduce Future Danger |work=Space.com. |date=February 12, 2019 |access-date=6 March 2019}}</ref> The project was led and operated by the Jet Propulsion Laboratory in Pasadena, with contributions from The University of Arizona, New Mexico State, Northern Arizona University, the Air Force Research Laboratory, and others.<ref name="1998 Mars Missions">{{cite web |date=December 1998 |title=1998 Mars Missions Press Kit |url=https://www.jpl.nasa.gov/news/press_kits/mars98launch.pdf |website=National Aeronautics and Space Administration |access-date=2020-11-05}}</ref>

The Deep Space 2 mission was intended to do an engineering validation of the concept of a penetrator probe, impacting the planet at high velocity, instead of slowing down for a soft landing as done by the probes conventionally used for planetary exploration. The penetrator concept is potentially a lower-cost approach, and has a proposed advantage of giving access to the subsurface of the planet being studied (in this case, Mars.)

Though the primary objective was to validate the technology, the probes also had goals for science analysis at Mars. These goals were “1) to derive the atmospheric density, pressure, and temperature throughout the entire atmospheric column, 2) to characterize the hardness of the soil and possibly the presence of layers at a scale of tens of centimeters, 3) to determine if ice is present in the subsurface soil, and, 4) to estimate the [[thermal conductivity]] of the soil at depth.”<ref name=":1">{{Cite journal|last1=Smrekar|first1=Suzanne|last2=Catling|first2=David|last3=Lorenz|first3=Ralph|last4=Magalhães|first4=Julio|last5=Moersch|first5=Jeffrey|last6=Morgan|first6=Paul|last7=Murray|first7=Bruce|last8=Presley|first8=Marsha|last9=Yen|first9=Albert|last10=Zent|first10=Aaron|last11=Blaney|first11=Diana|author11-link= Diana Blaney |date=1999|title=Deep Space 2: The Mars Microprobe Mission|journal=Journal of Geophysical Research: Planets|language=en|volume=104|issue=E11|pages=27013–27030|doi=10.1029/1999JE001073|bibcode=1999JGR...10427013S|issn=2156-2202|doi-access=|url=https://resolver.caltech.edu/CaltechAUTHORS:20140416-103953096 }}</ref> The eventual goal for such probes was to deploy networks “around a planet using no more resources than a single landing under conventional assumptions.”<ref>{{Cite web|last=Hecht|first=Michael H.|date=1996-01-15|title=Microinstruments and Micro Electromechanical Systems in Support of Earth and Space Science in the New Millennium |website=Jet Propulsion Laboratory |url=https://trs.jpl.nasa.gov/handle/2014/23645 |language=en-US |hdl=2014/23645 |hdl-access=free}}</ref>

The probes were launched with the Mars Polar Lander on January 3, 1999, on a [[Delta II]] 7425 Launch Vehicle.

===Spacecraft===
Each probe<ref name="Gavit1996">{{cite journal|last1=Gavit|first1=Sarah A.|last2=Powell|first2=George|title=The new Millennium Program's Mars Microprobe Mission|journal=Acta Astronautica|volume=39|issue=1–4|year=1996|pages=273–280|issn=0094-5765|doi=10.1016/S0094-5765(96)00145-2|bibcode=1996AcAau..39..273G}}</ref><ref name=":1" /> weighed {{convert|2.4|kg|abbr=on}} and was encased in a protective [[aeroshell]]. They rode to Mars aboard another spacecraft, the [[Mars Polar Lander]].

Upon arrival near the south polar region of Mars on December 3, 1999,<ref name="dates"/> the basketball-sized shells were released from the main spacecraft, plummeting through the atmosphere and hitting the planet's surface at over {{convert|179|m/s|abbr=on}}. On impact, each shell was designed to shatter, and its grapefruit-sized probe was to punch through the soil and separate into two parts. The lower part, called the forebody, was designed to penetrate as far as {{Convert|0.6|m|sp=us}} into the soil. It contained the primary science instrument on board, the Evolved Water Experiment.<ref name=":1" /> The upper part of the probe, or aftbody, was designed to remain on the surface in order to transmit data through its [[Ultra high frequency|UHF]] antenna to the [[Mars Global Surveyor]] spacecraft in orbit around Mars. The Mars Global Surveyor would act as a relay in order to send the data collected back to Earth. The two sections of the probe were designed to remain connected via a data cable.<ref name="NSSDC"/>

==Science Instruments==
The probes are each equipped with five instruments to enable analysis of the atmosphere, surface, and subsurface.

• ''Descent accelerometer:'' The descent accelerometer was a commercially available sensor meant to measure accelerations from drag during descent. Its readings could “be used to derive a density profile of the Martian atmosphere” based on the acceleration data combined with knowledge of the probe's speed and ballistic coefficient.<ref name=":2">{{Cite web |last=Blue |first=R. C. |date=1998-04-27 |title=Mars Microprobe Project Instrumentation Package |url=https://trs.jpl.nasa.gov/handle/2014/19235 |website=Jet Propulsion Laboratory |language=en-US |hdl=2014/19235 |hdl-access=free}}</ref>

• ''Impact accelerometer:'' The impact accelerometer was built with a range of ±120,000 g for the large expected acceleration on impact with Mars’ surface.<ref name=":2" />

• ''Meteorological sensor:'' provides atmospheric pressure and temperature data at the landing site. This sensor was located on the back of the probe so that it would stay above the surface after impact. It was sampled and recorded by the telecommunications “which enables the acquisition of meteorological data in the event that the microcontroller failed during the impact.”<ref name=":2" />

• ''Soil Thermal Conductivity Temperature Sensors:'' Twin platinum resistor temperature sensors would determine rates of cooling in the forebody once submerged in the surface.<ref name=":2" />

• ''Evolved Water Experiment:'' A small sample collection system in the forebody would bring Martian regolith into a heating chamber. The sample would then be heated to allow spectroscopy measurements on the resulting vapor using a miniaturized [[Tunable diode laser absorption spectroscopy|tunable diode laser]]. The Evolved Water Experiment was the primary instrument on board the probe.<ref name=":1" />

==New Technologies: High Impact and Low Temperature Electronics==
Custom electronics and batteries were designed for the Deep Space 2 probes to survive extremely high accelerations on impact with the surface of Mars and the cold temperatures that it would experience once in operation. Both the electronics and the custom cells were required to survive an impact on the order of 80,000 g and operational temperatures as low at -80&nbsp;°C.<ref>{{Cite conference |last1=Russell |first1=P.G. |last2=Carmen |first2=D. |last3=Marsh |first3=C. |last4=Reddy |first4=T.B. |last5=Bugga |first5=R. |last6=Deligiannis |first6=F. |last7=Frank |first7=H.A. |title=Development of a lithium/thionyl chloride battery for the Mars Microprobe Program |editor1=Harvey A Frank |editor2=Eddie T Seo |book-title=Thirteenth Annual Battery Conference on Applications and Advances  |year=1998 |pages=341–346 |publisher=IEEE |doi=10.1109/bcaa.1998.653891 |isbn=0-7803-4098-1 |s2cid=93199878}}</ref> Additionally, as much as a 30,000 g difference in acceleration was possible between the forebody and aftbody.<ref name=":3">{{Cite journal |last1=Rutnakumar |first1=B. |last2=Frank |first2=H. |last3=Kindler |first3=A. |last4=Deligiannis |first4=F. |last5=Davies |first5=E. |last6=Blakevoort |first6=J. |last7=Surampudi |first7=S. |date=1998-10-27 |title=DS2 Mars Microprobe Battery |url=https://trs.jpl.nasa.gov/handle/2014/20612 |website=Jet Propulsion Laboratory |language=en-US |hdl=2014/20612 |hdl-access=free}}</ref>

'''Batteries'''

Together with Yardney Technical Products, JPL designed a battery with two non-rechargeable 6-14V cells using Lithium-Thionyl Chloride (LI-SOCl2) chemistry to survive the expected conditions. The batteries were impact tested and also thermally cycled during development.<ref name=":3" />

'''Electronics Packaging'''

Due to the probe's form factor and the harsh survivability conditions, JPL used novel techniques to secure the onboard electronics. The techniques included chip-on-board (COB) technology to improve packing density.<ref name=":4">{{Cite conference |last1=Arakaki |first1=G. |last2=D'Agostino |first2=S. |date=March 1999 |title=New Millennium DS2 electronic packaging an advanced electronic packaging "sandbox" |book-title=1999 IEEE Aerospace Conference. Proceedings |id=Cat. No.99TH8403 |volume=2 |pages=205–213 |doi=10.1109/AERO.1999.793162 |bibcode=1999aero....2..205A |isbn=0-7803-5425-7 |s2cid=96712180}}</ref> It also used a 1-meter flexible umbilical cable to connect the forebody penetrator that would be displaced upon impact. Mechanical (non-functioning) models were impact tested before launch to determine if the structures would survive.<ref name=":4" />

== Mission failure ==
The probes reached Mars along with the Mars Polar Lander mission, apparently without incident, but communication was never established after impact. It is not known what the cause of failure was.

A failure review board was commissioned to report on the failures of the Mars Polar Lander and Deep Space 2 probes.<ref name=":0">{{cite web |url=ftp://ftp.hq.nasa.gov/pub/pao/reports/2000/2000_mpl_report_1.pdf |title=Report on the Loss of the Mars Polar Lander and Deep Space 2 Missions |publisher=[[Jet Propulsion Laboratory]] |archive-url=https://web.archive.org/web/20151213144413/ftp://ftp.hq.nasa.gov/pub/pao/reports/2000/2000_mpl_report_1.pdf |archive-date=2015-12-13 |url-status=dead |date=March 22, 2000 }}</ref> The review board was unable to identify a probable cause of failure,<ref name="report"/> but suggested several possible causes:
* The probe radio equipment had a low chance of surviving the impact.
* The batteries may have failed on impact.
* The probes may have bounced on impact.
* The probes may have landed on their sides, resulting in bad antenna performance or radio link geometry.
* The probes may simply have hit ground that was too rocky for survival.

The board concluded that the probes and their components were not tested adequately before launch.<ref name=":0" /><ref name="report">{{Cite press release |first=Thomas|last=Young|title=Testimony of Thomas Young, Chairman of the Mars Program Independent Assessment Team before the House Science Committee |version=Draft #7 3/13/00 |publisher=House Science and Technology Committee |url=http://www.spaceref.com/news/viewpr.html?pid=1444 |date=March 14, 2000 |access-date=April 22, 2009}}</ref>

{{Gallery
|File:DS-2 Components.jpg|Deep Space 2 penetrator
|File:Flight 1 probe of Deep Space 2 in Pre-Impact Configuration Microprobe-5.jpg|Deep Space 2 surface element
|Ds 2.jpg|DS-2 entry aeroshell
|Ds2.jpg|Visualization of Deep Space 2 as deployed after penetration
|File:DS2 Probe-anim.gif|DS2 functional animation
|file:DS2 components.png|DS2 probe components
}}

==Aftermath==

Despite the failures of Mars Polar Lander and the two Deep Space 2 probes, [[Planum Australe]], which served as their exploration target,<ref>{{cite news|url=https://www.americaspace.com/2019/01/06/could-not-have-survived-20-years-since-nasas-ill-fated-mars-polar-lander/|title='Could Not Have Survived': 20 Years Since NASA's Ill-Fated Mars Polar Lander|first=Ben|last=Evans|publisher=AmericaSpace|date=2019|accessdate=15 April 2022}}</ref> would in later years be explored by European Space Agency's [[MARSIS]] radar, which examined and analyzed the site from Mars' orbit and even determined that the area had water beneath its vast area of ice.<ref>{{cite journal |author=Orosei, R.|display-authors=etal|title=Radar evidence of subglacial liquid water on Mars |date=25 July 2018 |journal=[[Science (journal)|Science]] |volume=361 |issue=6401 |pages=490–493 |doi=10.1126/science.aar7268|arxiv=2004.04587 |pmid=30045881 |hdl=11573/1148029|doi-access=free |bibcode=2018Sci...361..490O }}</ref><ref>{{cite news |last1=Chang |first1=Kenneth |last2=Overbye |first2=Dennis |author-link2=Dennis Overbye |title=A Watery Lake Is Detected on Mars, Raising the Potential for Alien Life - The discovery suggests that watery conditions beneath the icy southern polar cap may have provided one of the critical building blocks for life on the red planet. |url=https://www.nytimes.com/2018/07/25/science/mars-liquid-alien-life.html |date=25 July 2018 |work=[[The New York Times]] |access-date=15 April 2022 }}</ref><ref>{{cite web |title=Huge reservoir of liquid water detected under the surface of Mars |url=https://www.eurekalert.org/pub_releases/2018-07/aaft-hro072318.php |work=[[EurekAlert]]|date=25 July 2018 |access-date=15 April 2022 }}</ref><ref>{{cite web |title=Liquid water 'lake' revealed on Mars |url=https://www.bbc.co.uk/news/science-environment-44952710 |work=[[BBC News]]|date=25 July 2018 |access-date=15 April 2022 }}</ref> Images which were obtained from MARSIS also determined that the water discovered beneath Planum Australe was in fact [[saltwater]].<ref>{{cite journal |author=Lauro, Sebastian Emanuel |display-authors=et al. |title=Multiple subglacial water bodies below the south pole of Mars unveiled by new MARSIS data |url=https://www.nature.com/articles/s41550-020-1200-6 |date=28 September 2020 |journal=[[Nature Astronomy]] |volume=5 |pages=63–70 |doi=10.1038/s41550-020-1200-6 |access-date=15 April 2022 |arxiv=2010.00870 |s2cid=244973225 }}</ref><ref>{{cite journal |last=O'Callaghan |first=Jonathan |title=Water on Mars: discovery of three buried lakes intrigues scientists - Researchers have detected a group of lakes hidden under the red planet's icy surface. |url=https://www.nature.com/articles/d41586-020-02751-1 |date=28 September 2020 |journal=[[Nature (journal)|Nature]] |doi=10.1038/d41586-020-02751-1 |pmid=32989309 |s2cid=222155190 |access-date=15 April 2022 }}</ref>

== See also ==
* [[Exploration of Mars]]
* [[Deep Space 1]]
* [[InSight]] – successful Mars lander carrying similar burrowing probe with temperature sensor
* [[List of missions to Mars]]
* [[List of spacecraft powered by non-rechargeable batteries]]

== References ==
{{Reflist}}

== Bibliography ==
* JPL, [https://mars.jpl.nasa.gov/msp98/ds2/fact.html Deep Space 2 Fact Sheet]
* NSSDC Data Archive, [https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=DEEPSP2 Deep Space 2]
* {{Cite press release | title=Press Kit: 1998 Mars Missions | format=.PDF | publisher=[[National Aeronautics and Space Administration]] | url=http://www2.jpl.nasa.gov/files/misc/mars98launch.pdf | date=December 8, 1998 | access-date=April 22, 2009}}

== External links ==
{{commons category|Deep Space 2}}
* [https://web.archive.org/web/20060102211248/http://nmp.jpl.nasa.gov/ds2/ Archived JPL Deep Space 2 website] (original website no longer exists)
* Report of the Loss of the Mars Polar Lander and Deep Space 2 Missions
**[https://web.archive.org/web/20151213144426/ftp://ftp.hq.nasa.gov/pub/pao/reports/2000/2000_mpl_report_1.pdf (Part 1)] (see page 10 of report (page 22 of this PDF) for the findings of the Deep Space 2 investigation)
**[https://web.archive.org/web/20151213144426/ftp://ftp.hq.nasa.gov/pub/pao/reports/2000/2000_mpl_report_2.pdf (Part 2)]
**[https://web.archive.org/web/20151213144426/ftp://ftp.hq.nasa.gov/pub/pao/reports/2000/2000_mpl_report_3.pdf (Part 3)]
**[https://web.archive.org/web/20151213144426/ftp://ftp.hq.nasa.gov/pub/pao/reports/2000/2000_mpl_report_4.pdf (Part 4)]
**[https://web.archive.org/web/20151213144426/ftp://ftp.hq.nasa.gov/pub/pao/reports/2000/2000_mpl_report_5.pdf (Part 5)] (see page 124 of report (page 1 of this PDF) for Deep Space 2 possible failure modes)

{{clear}}
{{Mars spacecraft}}
{{Jet Propulsion Laboratory}}
{{New Millennium Program}}

[[Category:1999 in spaceflight]]
[[Category:Derelict landers (spacecraft)]]
[[Category:Missions to Mars]]
[[Category:NASA space probes]]
[[Category:New Millennium Program]]
[[Category:Spacecraft launched by Delta II rockets]]
[[Category:Attached spacecraft]]
[[Category:Impactor spacecraft]]
[[Category:1999 on Mars]]