Tianwen-1

Launch data: Designation  45935 / 20049A Launch date  23 Jul 2020 - 04:41 UTC Launch site  Wenchang, LC101 Launch vehicle  CZ-5 Mission  Mars orbiter and Zhurong rover Heliocentric orbit: Perigee / Apogee  1.02 x 1.60 AU Eccentricity   Inclination  1.1° Period   min

Tianwen 1 cruise configuration Tianwen 1 orbiter

Tianwen 1 lander

Zhurong rover

Spacecraft data: Prime manufacturer   Platform   Operator   Mass at launch   kg Dry Mass  1645 kg Basic shape   Dimension (m)  about 4.0m high Equipment   Solar array  Solar cells Stabilization   Propulsion   DC power   Design lifetime

Tianwen-1 undergoing tests in 2019. The silver capsule on top houses the lander and rover, and the gold bottom half with the rocket engine is the orbiter.

Description:

• Tianwen 1 (formerly Huoxing 1) is a Chinese Mars mission comprising a lander/rover, orbiter and deployable camera that launched on 23 July 2020, and reaches Mars in February 2021. The scientific objectives of the mission are to study martian topography and geology, characterize the soil and its water-ice content, determine the composition of the surface material, profile the martian ionosphere, climate, and environment, and constrain the gravity and magnetic fields and the interior structure.
• Spacecraft and Subsystems:
  • The orbiter bus is a squat hexagonal cylinder with two solar panel wings and a high-gain dish antenna mounted on the sides. Thrusters and propellant tanks are mounted on the bottom of the bus. Communication is through the high-gain and a very low frequency antenna The scientific payload includes one high- and one moderate-resolution imaging camera, a subsurface detection radar, a mineralogy spectrometer, a magnetometer, an ion and neutral particle analyzer, and an energetic particle analyzer.
  • The Zhurong rover has a mass of about 240 kg. It has 6 wheels and a set of fold-out solar panels to provide power. A dish antenna is mounted on a mast at the back of the rover. Another mast at the front of the rover holds navigation and terrain cameras, and also a multispectral science camera. A magnetometer is also mounted on the mast. A cylindrical Mars climate detector containing atmospheric sensors and a surface component detector (laser-induced breakdown spectrometer) protrude from the top deck on the front of the rover. Subsurface detection radar components are mounted on the front face of the rover. The lander is primarily a landing platform for the rover and is not equipped for scientific studies.
• Mission Profile:
  • Tianwen 1 launched from Wenchang launch complex on a Long March 5 Y-4 booster on 23 July 2020 at 04:41 UT. The mission made a 7 month trip to Mars, arriving and going into orbit on 10 February 2021. Orbit was achieved at about 12:18 UT Earth Received Time (Time delay was 10 min., 40 sec.) or 20:18 Beijing Time after a 14-15 minute braking thruster firing. The initial orbit has an inclination of 10 degrees and an altitude of 400 x 180,000 km with a period of 10 days. The orbiter used high-resolution cameras to search for the nominal landing site for the lander and rover. They separated from the orbiter and made a landing in the Utopia Planitia region at 23:18 UT on May 14, 2021 (7:18 a.m. May 15 Beijing Time). The orbiter will then go into a 265 x 12,000 km altitude polar orbit, from which it will make scientific measurements and act as a relay for the rover communications with Earth. The Zurong rover rolled down a ramp onto the martian surface on 22 May at 2:40 UT (10:40 a.m. Beijing time). The rover is scheduled to operate on the surface for about 3 months.
  • The name Tianwen means "Questions to Heaven" the name of a poem by Qu Yuan. Huoxing is based on the Chinese word for "Mars". Zhurong is named after the Chinese god of fire.

Mission details:

• China′s first Mars probe was launched on Jul 23, 2020 from Wenchang in Hainan at 04:41 UTC. The CZ-5 rocket entered a 30 degree inclination parking orbit and then made a second burn from 0508 to 0517 UTC to reach escape velocity with C3 = 12.05 km2/s2. The probe and the second stage left Earth′s gravitational sphere on Jul 27 and entered a 1.02 x 1.60 AU x 1.1 deg solar orbit.
• The Tianwen 1 orbiter is about 4.0m high with estimated dry mass 1645 kg plus 1530 kg of propellant. Attached to it is a 1745 kg entry vehicle, containing a 1285 kg lander with a 7.5 kN throttlable engine, on top of which is a 240 kg, 0.8 x 2.0m rover. The orbiter will enter Mars orbit attached to the entry vehicle and will perform its deorbit burn. The lander will descend on aeroshell, parachuts and then its rocket engine.
• The mission was successfully launched from the Wenchang Spacecraft Launch Site, and is currently en route to Mars, having already traveled 29.4 million kilometers as of 9 October, 2020. Tianwen has so far completed two mid-course orbital corrections and performed self diagnostics on multiple payloads. The spacecraft has begun to conduct scientific operations with the Mars Energetic Particle Analyzer, mounted on the orbiter, which has already transmitted data back to ground control. Its objectives are to search for evidence of both current and past life, and to assess the planet′s environment.
  

  Planned orbital trajectory at Mars. Credit: Wikipedia

  Tianwen-1 transfer orbit and trajectory correction maneuvers. Credit: Wikipedia

  
  
• On 14 May 2021 (.96), almost 10 months after its launch, the rover made a successful touchdown on the northern hemisphere of Mars.
• As of 31 December 2021, the Zhurong rover was last known to have covered approximately 1500 meters of the Martian surface. It was difficult to maintain communication with the rover due to solar conjunction last month, which put it in safe mode. But according to the latest reports, the rover is back in action and safe to continue exploring. The rover has now been working for more than 255 Martian days, exceeding its expected 90 Martian day life expectancy.

External links:

• Serveveda.org: Probe Information
• Wikipedia: Probe Information
• Wikipedia: Huoxing-1
  
• Spacenews: Satellite description
• Satellite tracking (n2ya.com): Real time satellite tracking

Astrophilately covers:

Tianwen 1 launch. Credit: #411a

Succesful launch of the Mars probe. Credit: #411a