11. April 2019
A cubic metre of Mars

Tests for the In­Sight 'Mole'

HP3 model in the DLR test laboratory in Bremen
HP3 mod­el in the DLR test lab­o­ra­to­ry in Bre­men
Image 1/9, Credit: DLR (CC-BY 3.0)

HP3 model in the DLR test laboratory in Bremen

A ful­ly-func­tion­al mod­el of the Mars ‘Mole’ is be­ing test­ed on sand in a box at the DLR In­sti­tute of Space Sys­tems in Bre­men. Dur­ing the ex­per­i­ments, a seis­mome­ter, which can be seen on the sand in front of the HP3 ex­per­i­ment, ‘lis­tens’ to the ac­tiv­i­ty of the Mole.
DLR engineer Torben Wippermann with the HP3 experimental set-up
DLR en­gi­neer Tor­ben Wip­per­mann with the HP3 ex­per­i­men­tal set-up
Image 2/9, Credit: DLR

DLR engineer Torben Wippermann with the HP3 experimental set-up

The low­er part of a bal­loon is vis­i­ble above the HP3 ex­per­i­ment. This light­ens the ex­per­i­ment to sim­u­late the re­duced grav­i­ty con­di­tions found on Mars.
Testaufbau des HP3-Experiments am DLR in Bremen
HP3 mod­el in the DLR test lab­o­ra­to­ry in Bre­men
Image 3/9, Credit: DLR (CC-BY 3.0)

HP3 model in the DLR test laboratory in Bremen

A ful­ly-func­tion­al mod­el of the Mars ‘Mole’ is be­ing test­ed on sand in a box at the DLR In­sti­tute of Space Sys­tems in Bre­men. Dur­ing the ex­per­i­ments, a seis­mome­ter, which can be seen on the sand in front of the HP3 ex­per­i­ment, ‘lis­tens’ to the ac­tiv­i­ty of the Mole..
HP3 experiment on Mars
HP3 ex­per­i­ment on Mars
Image 4/9, Credit: NASA/JPL-Caltech/DLR

HP3 experiment on Mars

The hous­ing of the HP3 ex­per­i­ment moved slight­ly dur­ing ham­mer­ing.
Artist’s impression of the NASA InSight lander on the Martian surface
Artist’s im­pres­sion of the NASA In­Sight lan­der on the Mar­tian sur­face
Image 5/9, Credit: NASA/JPL-Caltech

Artist’s impression of the NASA InSight lander on the Martian surface

Launched on 5 May 2018, NASA’s In­Sight space­craft land­ed on 26 Novem­ber 2018 just north of the Mar­tian equa­tor, and de­ploy its so­lar pan­els. SEIS, an in­stru­ment for record­ing seis­mic waves (left of im­age), and HP3, an in­stru­ment de­vel­oped by DLR to mea­sure the ther­mal con­duc­tiv­i­ty of the Mar­tian re­golith and the heat flow from the in­te­ri­or of the plan­et (right of im­age), have been placed on the plan­et's sur­face.
HP3 cutaway rendering
HP3 cut­away ren­der­ing
Image 6/9, Credit: NASA/JPL-Caltech/DLR

HP3 cutaway rendering

An artist's con­cept of In­Sight's heat probe, called the Heat Phys­i­cal Prop­er­ties Pack­age, or HP³. This an­no­tat­ed cut­away ren­der­ing la­bels var­i­ous parts in­side of the in­stru­ment. JPL man­ages In­Sight for NASA's Sci­ence Mis­sion Di­rec­torate. In­Sight is part of NASA's Dis­cov­ery Pro­gram, man­aged by the agen­cy's Mar­shall Space Flight Cen­ter in Huntsville, Al­aba­ma. Lock­heed Mar­tin Space in Den­ver built the In­Sight space­craft, in­clud­ing its cruise stage and lan­der, and sup­ports space­craft op­er­a­tions for the mis­sion. A num­ber of Eu­ro­pean part­ners, in­clud­ing France's Cen­tre Na­tion­al d'Études Spa­tiales (CNES) and the Ger­man Aerospace Cen­ter (DLR), are sup­port­ing the In­Sight mis­sion. CNES and the In­sti­tut de Physique du Globe de Paris (IPGP) pro­vid­ed the Seis­mic Ex­per­i­ment for In­te­ri­or Struc­ture (SEIS) in­stru­ment, with sig­nif­i­cant con­tri­bu­tions from the Max Planck In­sti­tute for So­lar Sys­tem Re­search (MPS) in Ger­many, the Swiss Fed­er­al In­sti­tute of Tech­nol­o­gy (ETH Zurich) in Zurich, Switzer­land, Im­pe­ri­al Col­lege Lon­don and Ox­ford Uni­ver­si­ty in the Unit­ed King­dom, and JPL. DLR pro­vid­ed the Phys­i­cal Prop­er­ties Pack­age (HP³) in­stru­ment, with sig­nif­i­cant con­tri­bu­tions from the Space Re­search Cen­ter (CBK) of the Pol­ish Acade­my of Sci­ences and As­tron­i­ka in Poland. Spain’s Cen­tro de As­tro­bi­ología (CAB) sup­plied the wind sen­sors.
The HP3 Mole penetrometer
The HP3 Mole pen­etrom­e­ter
Image 7/9, Credit: DLR (CC-BY 3.0)

The HP3 Mole penetrometer

On 12 Febru­ary 2019 at 19:18 CET, DLR's Mars 'Mole' was re­leased on­to the Mar­tian sur­face with the robot­ic arm of the NASA lan­der In­Sight.
The InSight lander nearing its completion
The In­Sight lan­der near­ing its com­ple­tion
Image 8/9, Credit: NASA/JPL-Caltechn/Lockheed Martin Space

The InSight lander nearing its completion

Lock­heed Mar­tin Space con­struct­ed the In­Sight lan­der for NASA. The In­Sight lan­der will car­ry two ma­jor ex­per­i­ments, the Heat Flow and Phys­i­cal Prop­er­ties Probe (HP3) and the Seis­mic Ex­per­i­ment for In­te­ri­or Struc­ture (SEIS), to Mars, where a robot­ic arm will place them be­side the space­craft af­ter land­ing.
'Selfie' of the InSight lander on the Martian surface
'Self­ie' of the In­Sight lan­der on the Mar­tian sur­face
Image 9/9, Credit: NASA/JPL-Caltech

'Selfie' of the InSight lander on the Martian surface

In­Sight's first com­plete 'self­ie' on Mars. It shows the so­lar ar­rays and the plat­form of the lan­der. On the plat­form are its sci­en­tif­ic in­stru­ments and the UHF an­ten­na.
  • Various possible scenarios are being investigated to determine what caused the Mars ‘Mole’ to stop.
  • A fully functional model of the ‘Mole’ is being tested in a box of sand that compacts quickly and in which cavities can form as a result of the hammering.
  • Focus: Space, exploration

A blue box, a cubic metre of Mars-like sand, a rock, a fully-functional model of the Mars 'Mole' and a seismometer – these are the main components with which the German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt; DLR) is simulating the current situation on Mars. After its first hammering operation on 28 February 2019, the DLR Heat and Physical Properties Package (HP³), the Mars Mole, was only able to drive itself about 30 centimetres into the Martian subsurface. DLR planetary researchers and engineers are now analysing how this could have happened and looking into what measures could be taken to remedy the situation. "We are investigating and testing various possible scenarios to find out what led to the 'Mole' stopping," explains Torben Wippermann, Test Leader at the DLR Institute of Space Systems in Bremen. The basis for the scientists' work: some images, temperature data, data from the radiometer and recordings made by the French Seismic Experiment for Interior Structure (SEIS) during a brief hammering test conducted on 26 March 2019.

When the NASA InSight lander arrived on the Martian surface, everything looked even better than expected. Although the lander's camera showed numerous rocks some distance away, the immediate surroundings were free of rocks and debris. The reason why the 'Mole' hammered its way quickly into the ground after being placed on the surface of Mars and was then unable to continue its progress is now being diagnosed remotely. "There are various possible explanations, to which we will have to react differently," says Matthias Grott, a planetary researcher and the HP³ Project Scientist. A possible explanation is that the 'Mole' has created a cavity around itself and is no longer sufficiently constrained by the friction between its body and the surrounding sand.

Another type of sand

In Bremen, DLR is now experimenting with a different type of sand: "Until now, our tests have been conducted using a Mars-like sand that is not very cohesive," explains Wippermann. This sand was used during earlier tests in which the 'Mole' hammered its way down a five-metre column in preparation for the mission. Now, the Mole's ground model will be tested in a box of sand that compacts quickly and in which cavities can be created by the hammering process. During some of the test runs, the researchers will also place a rock with a diameter of about 10 centimetres in the sand. Such an obstacle in the subsurface could also be the reason why the HP³ instrument has stopped penetrating further. In all experiments, a seismometer listens to the activity of the Earth-based 'Mole'. During the short 'diagnostic' hammering on Mars, SEIS recorded vibrations to learn more about the Mole's impact mechanism. Comparisons between the data obtained on Mars and the Earth-based tests help the researchers more closely understand the real-life situation. "Ideally, we will be able to reconstruct the processes on Mars as accurately as possible."

'Moles' on Earth as guinea pigs

The next steps will follow once the scientists know what caused the progress of the 'Mole' to come to a halt on 28 February 2019. Possible measures to allow the instrument to hammer further into the ground must then be meticulously tested and analysed on Earth. For this reason, a replica of the HP3 instrument has been shipped to NASA's Jet Propulsion Laboratory in Pasadena, California. There, the DLR researchers' findings can be used to test the interaction of the 'Mole', the support structure and the robotic arm to determine whether, for example, lifting or moving the external structure is the correct solution. "I think that it will be a few weeks before any further actions are carried out on Mars," says Grott. The break in activities for the Mars Mole will only come to an end once a solution has been found for the Earth-based 'Moles'.

The HP³ Instrument on NASA’s InSight mission

The InSight mission is being carried out by NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, California, on behalf of the agency’s Science Mission Directorate. InSight is part of NASA’s Discovery Program. DLR is contributing the Heat Flow and Physical Properties Package (HP³) experiment to the mission. The scientific leadership lies with the DLR Institute of Planetary Research, which was also in charge of developing and implementing the experiment in collaboration with the DLR Institutes of Space Systems, Optical Sensor Systems, Space Operations and Astronaut Training, Composite Structures and Adaptive Systems, and System Dynamics and Control, as well as the Institute of Robotics and Mechatronics. Participating industrial partners are Astronika and the CBK Space Research Centre, Magson GmbH and Sonaca SA, the Leibniz Institute of Photonic Technology (IPHT) as well as Astro- und Feinwerktechnik Adlershof GmbH. Scientific partners are the ÖAW Space Research Institute at the Austrian Academy of Sciences and the University of Kaiserslautern. The DLR Microgravity User Support Center (MUSC) in Cologne is responsible for HP³ operations. In addition, the DLR Space Administration, with funding from the German Federal Ministry for Economic Affairs and Energy, supported a contribution by the Max Planck Institute for Solar System Research to the French main instrument SEIS (Seismic Experiment for Interior Structure).

Detailed information on the InSight mission and the HP³ experiment is available on DLR’s dedicated mission site with extensive background articles. You can also find information in the animation and brochure about the mission or via the hashtag #MarsMaulwurf on the DLR Twitter channel. Tilman Spohn, the Principal Investigator for the HP³ experiment, is also providing updates in the DLR Blog portal about the activities of the Mars Mole.

Written by Manuela Braun

Contact
  • Falk Dambowsky
    Ed­i­tor
    Ger­man Aerospace Cen­ter (DLR)
    Me­dia Re­la­tions
    Telephone: +49 2203 601-3959
    Fax: +49 2203 601-3249
    Linder Höhe
    51147 Cologne
    Contact
  • Prof.Dr. Tilman Spohn
    HP³ Prin­ci­pal In­ves­ti­ga­tor
    Ger­man Aerospace Cen­ter (DLR)

    DLR In­sti­tute of Plan­e­tary Re­search
    Telephone: +49 30 67055-300
    Fax: +49 30 67055-303
    Linder Höhe
    51147 Köln
    Contact
  • Christian Krause
    Ger­man Aerospace Cen­ter (DLR)

    Mi­cro­grav­i­ty Us­er Sup­port Cen­ter (MUSC), Space Op­er­a­tions and As­tro­naut Train­ing
    Telephone: +49 2203 601-3048
    Linder Höhe
    51147 Köln
    Contact
  • Matthias Grott
    Ger­man Aerospace Cen­ter (DLR)
    In­sti­tute of Plan­e­tary Re­search
    HP³ project sci­en­tist and In­Sight sci­ence team mem­ber; Fo­cus on heat flow and ther­mal con­duc­tiv­i­ty mea­sure­ments; In­stru­ment de­vel­op­ment
    Rutherfordstraße 2
    12489 Berlin
    Contact
  • Torben Wippermann
    Ger­man Aerospace Cen­ter (DLR)
    In­sti­tute of Space Sys­tems
    Telephone: +49 421 24420-1120
    Robert-Hooke-Straße 7
    28359 Bremen
  • Dr Anko Börner
    Ger­man Aerospace Cen­ter (DLR)
    In­sti­tute of Op­ti­cal Sen­sor Sys­tems
    In­sti­tute of Op­ti­cal Sen­sor Sys­tems
    Telephone: +49 30 67055-509
    Rutherfordstraße 2
    12489 Berlin-Adlershof
  • Dr Roy Lichtenheldt
    Ger­man Aerospace Cen­ter (DLR)
    Sys­tem Dy­nam­ics and Con­trol
    Telephone: +49 8153 28-3095
    Fax: Institute of System Dynamics and Control
    Münchener Straße 20
    82234 Weßling
  • Martin Knapmeyer
    Ger­man Aerospace Cen­ter (DLR)
    In­sti­tute of Plan­e­tary Re­search
    Telephone: +49 30 67055-394
    Rutherfordstraße 2
    12489 Berlin
    Contact
  • Jörg Melcher

    DLR In­sti­tute of Com­pos­ite Struc­tures and Adap­tice Sys­tems
    Telephone: +49531295-2850
    Fax: +49531295-2875
    Contact
  • Marco Scharringhausen
    Deutsches Zen­trum für Luft- und Raum­fahrt (DLR)
    In­sti­tut für Raum­fahrt­sys­teme
    Telephone: +49 421 24420-1106
    Robert-Hooke-Str. 7
    28359 Bremen
    Contact

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