Mars Pathfinder (Discovery 2)

Launch data: Designation  24667 / 96068A Launch date  04 Dec 1996 - 06:58 UT Launch site  CC, LC-17B Launch vehicle  Delta-7925 Mission  Mars lander Heliocentric orbit Perihelion / Aphelion   Incl. to ecliptic   ° Period   min

Spacecraft data: Prime contractor  Jet Propulsion Lab (JPL) Operator  NASA/JPL Platform   Mass at launch  890 kg Lander Mass  360 kg Microrover Mass  16 kg Basic shape   Dimension   Solar array   Stabilization   DC power   Design lifetime

Mars-Pathfinder lander-rover

Decay:

Mission details:

• NASA's Mars Pathfinder (MPF) space probe was successfully launched on Dec 4, 1996 from Cape Canaveral. Pathfinder will land in Ares Vallis on 1997 Jul 4. The space probe consists of a cruise stage, an atmospheric entry aeroshell, a lander, and the tiny Sojourner rover which will use an x-ray spectrometer to study the composition of Martian rocks near the landing site.
• The McDonnell Douglas Delta 7925 rocket took off from Launch Complex 17B, and the second stage and payload entered a 28 degree inclination elliptical earth parking orbit. The second stage ignited again an hour after launch to raise orbit, followed immediately by the third stage which propelled MPF into solar orbit. After its depletion burn, the second stage ended up in a 148 x 3119 km x 36.4 deg orbit.
• MPF was originally part of the MESUR Mars Environmental Survey; that program was abandoned and MPF became one of the Discovery series of planetary missions (like the NEAR asteroid probe). The companion MGS probe launched on Nov 7 is a Mars Surveyor, which is technically a separate NASA program.
• The Mars Pathfinder (MPF) space probe landed on Mars at 1656 UTC on Jul 4, 1997. Mars Pathfinder is part of NASA's Discovery program.
  The spacecraft consists of:
  
  • a cruise stage, which separates prior to entry into the Martian atmosphere
  • an aeroshell, which protects the lander during atmospheric entry,
  • main parachute, 12.7m diameter
  • backshell with RAD Rocket Assisted Decelerator, which brakes the craft just before touchdown,
  • a set of airbags which inflate prior to touchdown,
  • the MPF lander itself,
  • the MFEX (MicroRover Flight Experiment), or Sojourner, a small 10 kg automated vehicle.
• MPF was built by the Jet Propulsion Lab (JPL), which also controls the mission. The lander has a camera and a meteorology experiment. The rover has an X-ray spectrometer to study the composition of rocks at the landing site.
• MPF landed in the Ares Vallis region of Mars at 19.33 N 33.55 W, southeast of the Tharsis volcanoes and of the Viking 1 landing site. The cruise stage separated at 1622 UTC. The aeroshell entered the Martian atmosphere at an altitude of 125 km at 1652 UTC. At 1654 UTC the parachute deployed, and at 1655 UTC the aeroshell separated from the lander. The rockets fired, the airbags inflated, and the MPF lander reached the surface at about 1656 UTC, landing on its base petal.
• It appears later that the lander made about 15 bounces before coming to rest and rolled about 1 km.
• The light travel time from Mars to Earth is 10 minutes and 40 seconds. At around 1706 UTC transmissions from the surface were received at JPL. The airbags then were slowly deflated, and at around 1800 UTC the side petals deployed to orient the lander correctly. Confirmation of petal deployment was received at 1836 UTC. The first pictures of the surface show an uneven landscape with many rocks and large hills on the horizon. Controllers plan to adjust the petals and airbags before deploying the rover, as the petal on which the rover sits is tilted a little high. The rover is also having problems communicating with the lander (and thus with Earth).
• Viking Lander 1 was originally meant to land on July 4, 1976 on the rougher A-1 site. When Viking 1 reached Mars orbit in Jun 1976 and started imaging site A-1, JPL decided that the terrain was too rough, and delayed the landing while they searched for a smoother site, eventually settling on the Chryse Planitia site where Viking landed on 1976 Jul 20.
  Mars Pathfinder was able to land on the rougher A-1 site, on July 4, 1997, because of its robust airbag landing system, and indeed the rocky images from "Sagan Memorial Station" suggest that it was a really good thing Viking didn't try landing there.
• On Jul 5, the lander was renamed the Carl Sagan Memorial Station. Early on Jul 6, the Sagan Station deployed the rover ramps. A few hours later the Sojourner rover rolled down the ramps and it is now on the Martian surface.
• JPL announced the end of the Mars Pathfinder mission; last signal detected from the Sagan Memorial Station was on Oct 6, 1997.