Editing Deep Space 2 (section)

== 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"/>