NASA's Mars InSight module is expected to hit the red planet on Monday, giving scientists their first detailed view of the Martian interior.
InSight is based on the 2008 Phoenix Lander, which used remnant components from the canceled Mars Surveyor 2001 lander.
Nasa prefers not to talk much about Surveyor since the ax was used on the unfortunate spacecraft following the 1999 Mars Polar Lander crash that erased NASA's excellent notebook to land on the Martian surface.
Phoenix, however, was a great success, and the stationary probe exceeded NASA's expectations by surviving almost twice the 90-day Martian suns planned for the mission before succumbing to dust and cold in a way that we hope fervently that Opportunity does not have.
Taking a "no broken, do not fix" approach, Jet Propulsion Lab (JPL) engineers took the Phoenix probe project and adapted it to InSight. The 360kg landing module (once on the ground) has two solar panels, each 2.2m in diameter, and will have something between 0.8 and 1.1m in height, depending on how much the legs compress into the landing.
Unlike Phoenix, NASA said it expected InSight to survive nearly two years on the surface. Solar panels should provide 600-700W on a clear day from Mars and 200-300W when covered with dust.
The power, which NASA has estimated would be enough to run a household blender, will power the three main instruments carried by the probe.
The 50 kg payload includes the Seismic Experiment for Internal Structure (SEIS), the Heat Flow Probe and Physical Properties (HP3) and the Rotation and Interior Structure Experiment (RISE).
The probe is also equipped with a robotic arm that will use to place HP3 and RISE on the surface of the planet. By putting the equipment in direct contact with the Martian dirt, scientists hope to avoid the problems experienced by the Viking landers of the 1970s, where probe seismometers captured the vibrations of the spacecraft itself and not the planet.
HP3 also has some digs to do. Tricky from the Lander deck.
The SIX, provided by the National Center for Space Studies of France (CNES), is a dome-shaped instrument containing three pendulums that detect the seismic vibrations of Mars.
The scientists said the data returned from the instrument will provide a glimpse of the planet's internal activity and structure. Researchers crossed their fingers to detect the liquid water scattered beneath the surface as well as the volcanoes active underground.
The HP3 heat probe will drill nearly five meters below the surface of the planet after being deposited by InSight's robotic arm. The purpose of the instrument is to provide a definitive measure of the heat still flowing from the interior of Mars.
The probe will excavate considerably deeper than the 2 meters planned for the ESA ExoMars rover (although the latter is a little more mobile) and much more than the previous NASA landing systems, which mainly scratched the surface.
According to lead instrument investigator Tilman Spohn, the instrument will tell scientists if Mars and Earth formed from the same "things", giving a clue as to how the rocky bodies in the solar system evolved.
The last major instrument of the mission, RISE, will accurately track the location of the module to determine how much the North Pole of Mars "rocks" when the planet orbits the sun. Scientists will use the data to determine the size of the iron-rich core of the Sea, as well as what other elements may be present.
The instrument, mounted on the module deck, will also indicate whether the core is liquid or solid.
Deep Space Cube
Along the journey to Mars there are two CubeSats, MarCO-A and B communications relays. The suitcase-sized spacecraft were planned as demonstrators, but as both worked wonderfully en route to the Red Planet as independent pamphlets, they would provide a short relay to InSight as the lander heads to the surface.
The radios of the size of cricket balls in the Marco can receive in UHF and both transmit and receive in band X, therefore they must be able to transmit immediately the data received back to Earth. The lander will be broadcasting information during the landing, descent and landing in the UHF band to NASA's Mars Reconnaissance Orbiter, which can not simultaneously receive in one band and transmit in another. So without Marco, Earth's nervous engineers could come across a wait of over an hour for InSight news.
If the tiny spacecraft is viable, NASA experts said the technology could have applications in other parts of the solar system and at least allow a "bring your own relay" communication option during critical landing phases.
The landing timeline – reaching the right tone
The fun begins today at 2:40 pm EST, when the spacecraft separates from the cruise stage that took it to Mars. A minute later, InSight is set to enter before entering the rarefied atmosphere of the red planet, starting at 14:47 EST and traveling at 12,300 mph.
Two minutes later, engineers anticipate that the probe's heat shield will reach about 1,500 ° C, or peak heating. 15 seconds later, the spacecraft will experience a maximum deceleration which, along with the heating, could make the radio contact somewhat unstable.
At 14:51 EST, the parachute will be launched, with the heat shield ejected seconds later. 14:52 EST will see the radar on to detect ground clearance. Shortly afterwards, the launcher's retro rockets will fire and InSight will decrease to a constant of 5 mph before landing at 14:54 EST. InSight will send a tone back to Earth at 15:01 EST to indicate that it is safe.
The tone is important and is part of a sequence that Earth engineers will be listening to as InSight passes each landing frame. While the tone itself does not carry much in terms of information, they give a clue as to what is happening. For example, when the parachute is deployed, InSight slows down, which in turn changes the signal frequency.
Two Earthbound radio telescopes, the Green Bank Observatory in West Virginia, and the Max Planck Institute in Efflesberg, Germany, will be trained on Mars, hoping to detect the signals in case experimental MarCOs do not play ball. The MRO data will be transmitted to Earth around 18:00 EST, three hours after landing. Finally, the long-lived Mars Odyssey transmitter from 2001 will send its own recording of landing events to 20:35 EST, including confirmation that vital solar arrays have been deployed.
However, if everything works the way the engineers expect, and the Marcos do their thing, the buttocks will be released at 3:04 EST, when the first images of the lander land on the screens of the Earth.
US investment in InSight so far is $ 813.8 million, including $ 163.4 million to actually launch the thing. France and Germany contributed about $ 180 million to the SIX and HP3, respectively. And those CubeSats? A cut of about $ 18.5 million. ®