What is the Nasa Osiris Rex Mission?

Osiris Rex is a mission of Nasa. The aim of the mission is to bring back a sample from the asteroid Bennu to earth. Osiris Rex is the abbreviation for “Origins Spectral Interpretation Resource Identification Security – Regolith Explorer”. 

The mission started on Sept. 8, 2016. The spacecraft was launched from Cape Canaveral Air Force Station. An Atlas V rocket carried the spacecraft to space. The spacecraft Osiris Rex travelled for over 2 years until it enter the orbit around the asteroid Bennu on December, 31st. Osiris Rex travelled 228,931,288 km (142,251,307 mi) and reached a speed of 133,441 km/h (83,400 mph).

Osiris Rex is the third spacecraft of the New Fronti133,441 km/h (83,400 mph).ers Program of Nasa next to the New Horizon and Juno spacecraft. The cost of the Osiris Rex mission is 800 Million USD.

The decision for the Osiris Rex mission was taken in 2011 on May 25th.

osiris-rex-diagram_without_labels

Osiris Rex has the shape of a cuboid. It measures 3.1 m in width and 2.72 m heigh. The weight at launch of Osiris Rex on earth was 880 kg. The solar pannels (D) have a total size of 8.5 sqr meters.

Osiris Rex carries the following instruments:

  • OCAMS (OSIRIS-REx Camera Suite)
  • OVIRS (OSIRIS-REx Visible and IR Spectrometer)
  • OTES (OSIRIS-REx Thermal Emission Spectrometer)
  • OLA (OSIRIS-REx Laser Altimeter)
  • REXIS (Regolith X-ray Imaging Spectrometer)
  • TAGSAM (Touch-And-Go Sample Acquisition Mechanism)

In summer 2020 Osiris Rex will try to collect a 60g sample of hydrated, carbon-rich material from the asteroid Bennu.  The sampling site chosen on the asteroid Bennus is called after the bird Nightingale. The sampling site is near the north pole of the asteroid Bennu. The asteroid Bennu itself has a width of approximate 500 m. There are several reasons why this sampling site was chosen. It has lots of fine grained material. The temperature have always been very cool at the north pole. The dirt and rubble therefore have not had much alterations through heat.  The landing site is in a crator and only 20 m wide. Osiris Rex will need 6 m.

The sampling date is set for August, 25th 2020. In case the first collection fails Osiris Rex has still 2 more attempts to collect the sample. The mission will likely end in the first half of 2021. Over 100 people have dedicated thousand of hours to this mission.

This is the way the landing is planned:

On January 21, 2020 the OSIRIS-Rex spacecraft successfully OSIRIS-REx successfully performed a flyover of the sampling site Nightingale. It changed from the save orbit with a distant of 1.2 km to a distant of 620 m. After 11 hourse it returned to save orbit distance of 1.2 km.

Osprey is the second backup sampling site for Nightingale: see https://twitter.com/OSIRISREx/status/1205193577573150721?s=20
OspreyJpeg

The location is of Osprey is close to the Nightingale sampling site: see https://twitter.com/OSIRISREx/status/1205185345119064064?s=20

NigthinggaleOsprey

After Osprey the other back up sample sites are called Sandpiper and Kingfisher:

An overview of the asteroid Bennu and the sampling sites are given in this video:

 

Osirix-Rex has been scanning the asteroid Bennu for a year from a distance of 1.75 km. With this data the optimal sampling sites have been selected. As Osiris Rex discovered more rocks and boulders than envisioned over 3500 citizen scientists were involved to mark rocks, measure boulders, and map craters. Over 14 million annotations were collected in this so called CosmoQuest’s Bennu Mappers project based at the Planetary Science Institute in Tucson, Ariz. (CosmoQuest.org). http://www.bizsiziz.com/the-citizen-scientists-who-helped-map-bennu/

The OSIRIS-Rex spacecraft team will measure the sample mass by spinning the spacecraft before and after sampling. The collected sample mass will change the inertia of the spacecraft.

There is a live tracker for the Osiris Rex spacecraft: https://spacein3d.com/mission/osiris-rex. Current distance from earth is 270,308,918 (167,962,175). Osiris Rex also holds the record for the closest orbit around a space body.

Soon after the arrival Osiris Rex discovered Bennu to be an active asteroid. Bennu from time to time will eject particles into space. Some of these particles will after orbiting fall back while the others will escape into space. The first of such ejection was observed on Januar 6, 2019. There are several reasons for the ejections. One of them is thermal fracturing. https://www.nasa.gov/feature/goddard/2019/osiris-rex-explains-bennus-mysterious-particles

Dante Lauretta of the University of Arizona, Tucson, is the principal investigator for OSIRIS-REx, and the University of Arizona also leads the science team and the mission’s science observation planning and data processing. He will share updates on Dante Lauretta twitter account.

Official website of the Osiris Rex Mission: https://www.asteroidmission.org/

The Spaceship Weekly

 

 

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