InSight Sol 71 image taken by Instrument Deployment Camera (IDC) on February 7, 2019. German Heat Flow and Physical Properties Package (HP3) is seen at left of robotic arm.
Credit: NASA/JPL-Caltech

NASA’s InSight Mars lander is nearing its next major milestone mission by deploying the German Heat Flow and Physical Properties Package (HP3).

Like the seismometer and Wind and Thermal Shield, the HP3 will be placed on the surface of Mars by InSight’s robotic arm.

InSight Sol 73 photo acquired by Instrument Deployment Camera (IDC) on February 9, 2019 shows the robotic arm grapple hovering over HP3.
Credit: NASA/JPL-Caltech

Plowing deeper

HP3 is designed to burrow down beneath the Red Planet’s topside — with its tether embedded with heat sensors — to a depth of 16 feet (five meters). If successful, the HP3 will plow deeper than any previous arms, scoops, drills or probes before it.

In an earlier email exchange with Inside Outer Space, Tilman Spohn, HP3’s principal investigator at the German Aerospace Center’s Institute of Planetary Research in Berlin, Germany projected a February 13th deployment of the device on the Red Planet’s surface, and the start of operations about a week later.

“However, be aware that these dates are still not cast in concrete yet,” Spohn added.

Ready to go!

In a recent update from Tilman: “We are ready to go!”

The InSight lander grapple has been moved to the HP3 “teachpoint” that is immediately above the grapple hook on the instrument.

Tilman adds that over this weekend the grapple will catch the hook and after confirmation on Monday, the commands for HP3 deploy will be uplinked.

This command will then be executed on Mars on Tuesday February 12 (in the late morning on Mars, with touchdown of the instrument to be expected at 10:46 local time). “We expect the confirmation to be downlinked around 4pm PST,” Tilman explains.

Hammer time

Imagery from the Interior Exploration using Seismic Investigations, Geodesy and Heat Transport (InSight) lander show the robotic arm in position for grapple of the HP3.

Components of the HP3 heat flow probe. Top left: the radiometer (RAD), which is used to measure the radiation temperature (roughly equivalent to the ground temperature) of the surface. Right: the casing with the mole penetrometer, the temperature measuring cable (TEM-P) and the data cable (ET) connected to the lander. In addition, the casing contains an optical length meter for determining the length of the temperature measuring cable that has been pulled from the casing. The mole contains the TEM-A active thermal conductivity sensor and the STATIL tiltmeter. Bottom left: the electronic control unit, known as the back end electronics (BEE), which remains on the lander and is connected to the probe via the ET.
Credit: DLR.

Once on the surface, HP3 can take Mars’ temperature to reveal how much heat is still flowing out of the interior of the planet.

Weighing a little over 6.5 pounds (about 3 kilograms) HP3’s “Mole” hammers itself under the surface. A maximum of 2 watts of power is available while burrowing underneath the surface.

The German Aerospace Center’s (DLR) HP3 heat flow probe has the Mole pulling a ribbon cable equipped with 14 temperature sensors behind it. Once the probe has reached its target depth, the temperature will be measured by all of the sensors every 15 minutes for several months.

Credit: DLR/Screengrab/Inside Outer Space

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