Screenshot from NASA Webcast of the launch of Mars InSight. It’s a foggy start on going to Mars
Mission Rundown: ULA - Atlas V 401- Mars InSight
Written: December 1, 2022
Marco Polo got InSight to Mars
NASA’s InSight mission began a six-month journey to Mars on Saturday May 5, 2018 with liftoff aboard United Launch Alliance’s Atlas V 401 rocket. The first interplanetary mission to launch from the West Coast of the United States, InSight departed from launch pad SLC-3E on California’s Vandenberg Air Force Base at the opening of a two-hour launch window that opened at 04:05 PDT - 11:05 UTC.
InSight will land on Elysium Planitia, an equatorial region or Mars, from where it will perform experiments aimed at gaining a better understanding of the Red Planet’s interior. The twelfth mission of NASA’s Discovery program, InSight will be joined on its journey to Mars by Mars Cube One (MarCO) a pair of small satellites that will test the operation of miniaturized spacecraft technology in deep space and help to relay data from the InSight lander as it descends into the Martian atmosphere.
InSight – Interior Exploration using Seismic Investigations, Geodesy and Heat Transport – is the first mission dedicated to understanding the internal structure of Mars.
Graphic of InSight’s on Mars with all instruments up and running. It didn’t land near an edge
The mission is expected to last at least about two Earth years – or one Martian year. Originally named the Geophysical Monitoring Station (GEMS), and also known as Discovery 12, the InSight mission is led by NASA’s Jet Propulsion Laboratory (JPL) with Bruce Banerdt as principal investigator.
The InSight Payload
The primary goals of the InSight mission are to help gain an understanding of how the terrestrial planets formed and evolved by studying the interior of Mars, and to determine current seismic and impact activity on Mars. The specific objectives of the mission are to determine the thickness and structure of Mars’ crust, the composition and structure of its mantle and the size, composition and physical state of its core. Other key objectives are to characterize the thermal state of the planet’s interior, to measure seismic activity and the rate of meteorite impacts on the surface.
The Seismic Experiment for Interior Structure (SEIS) is a seismometer consisting of three very broad-band sensors to detect medium-to-low frequency seismic activity and three short-period sensors to detect more high-frequency activity. The SEIS instrument package will be deployed onto the surface of Mars, with an umbilical connection to InSight providing electrical connections for power and data. SEIS will detect and measure seismic activity, including “mars-quakes”, surface impacts and gravitational interactions with Mars’ larger moon, Phobos. The instrument was built by an international consortium involving several European nations and led by French Space Agency CNES.
The Heat Flow and Physical Properties Probe, or HP3, will tunnel into the Martian surface to study the amount of internal heat escaping from the interior of Mars through its surface. HP3 will deploy a device called a self-hammering mole, which will use a spring-loaded tungsten block to force itself under the surface.
The Rotation and Interior Structure Experiment (RISE) will aim to characterize Mars' axis of rotation. By understanding perturbations in the rotation of Mars, scientists will be able to gain an understanding of the size, density and state of Mars’ core. The investigation will use NASA's Deep Space Network to communicate with InSight’s X-band transponder, with the radio signals being used to determine the spacecraft’s position to with 10 centimeters (4 inches) accuracy and to look for changes as Mars rotates. The experiment builds on research conducted by the Mars Pathfinder mission in 1997.
InSight’s Auxiliary Payload Sensor Subsystem (APSS) consists of additional instruments to monitor the environment around the spacecraft. This includes a fluxgate magnetometer – the first magnetometer to be carried by a Mars lander – which will monitor the magnitude and orientation of Mars’ magnetic field at InSight’s landing site.
Other instruments in this suite include Temperature and Wind for InSight (TWINS), a pair of booms carrying temperature and wind sensors to monitor atmospheric conditions and atmospheric pressure sensor.
In addition to APSS, the HP3 instrument and cameras aboard InSight spacecraft will also help to gain an understanding of conditions at the landing site, tracking variations in surface temperature and monitoring dust that is picked up by the wind respectively.
The Italian Space Agency, ASI, has provided the Laser Retroreflector for Mars, LaRRI, which InSight will carry to the surface. LaRRI is a 5-centimeter (2-inch) diameter retroreflector array, incorporating eight reflectors. The retroreflectors reflect incoming light directly back at its source, which will allow future orbiter missions to measure the lander’s position with great precision.
InSight’s Instrument Deployment System (IDS) consists of a 2.4-metre (7.8-foot) three jointed robotic arm and cameras to identify suitable deployment sites for the instruments and monitor the process of lowering them to the surface. The Instrument Deployment Arm (IDA) will place SEIS and HP3 onto the surface and will also be used to place a shield around SEIS to protect it from wind and thermal conditions.
IDS incorporates two one-megapixel engineering cameras – the Instrument Deployment Camera (IDC) and the Instrument Context Camera (ICC). The IDC is mounted between the elbow and wrist joints of the lander’s robotic arm, while ICC is mounted under the deck of the lander, allowing it a view of the area to the south of the lander where the instruments will be placed.
Lockheed Martin was the prime contractor for the InSight mission, with construction beginning in May 2014. The spacecraft has a mass at launch of 694 kilograms (1,530 lb). Its lander will stand 83 to 108 centimeters tall (2.7 to 3.5 feet), depending on how much its legs compress after landing, with the spacecraft measuring 1.56 meters (5.12 feet) in width, or 6 meters (19.69 ft) across with its solar panels fully deployed.
In addition to the lander itself, InSight consists of a coast stage and an aeroshell, which will support the spacecraft during the journey to Mars and its entry into the Martian atmosphere respectively. The lander has a mass of 358 kilograms (890 lb), not including 67 kilograms (148 lb) of propellant, while the aeroshell weighs 189 kilograms (418 lb) and the cruise stage has a mass of 79 kilograms (174 lb).
InSight’s cruise stage provides power – via solar panels – and communications during the journey to Mars. It is equipped with star trackers and sun sensors to help guide the spacecraft, but does not carry any propulsion systems. Instead, engines on the lander will be used for attitude control and course corrections during the mission’s coast towards Mars. Although the lander is encapsulated within its aeroshell, cut-outs allow some of the spacecraft’s thrusters to operate prior to aeroshell separation. The aeroshell itself includes a back shell and heat shield.
The lander is equipped with twenty engines – twelve 302-newton (68 pound-force) descent engines to perform its landing, four 22-newton (5 lb) trajectory correction thrusters for performing maneuvers during the coast phase and four 4.4-newton (1 lb) reaction control system (RCS) thrusters for attitude control. Only the trajectory correction and RCS thrusters will be used during the coast phase.
All of these thrusters are monopropellant, using hydrazine that is passed over a heated catalyst to generate thrust without requiring a separate oxidizer.
Once on the surface of Mars, InSight will deploy two near-circular solar panels to generate power. Each panel is 2.15 meters (7.05 feet) in diameter, with a decagonal shape. Combined, the panels will generate up to 700 watts of power on a clear day, or 200-300 watts if conditions are dusty.
The lander will use radiators and heat pipes to dissipate heat, while auxiliary heaters can also be used to raise the spacecraft’s temperature where necessary.
The Atlas V Launch
The InSight mission was the fifteenth launch of an Atlas V from Space Launch Complex 3E and the forty-sixth launch from SLC-3E overall.
Wet Dress Rehearsal on SLC-3E with a fairingless Atlas V while the mobile service is rolled away
Unlike at Cape Canaveral, where Atlas is prepared for launch on a mobile launch platform in the Vertical Integration Facility (VIF), placed away from the launch pad, at Vandenberg integration of the rocket takes place on the pad. Atlas is lifted up and built inside a mobile service tower, which is then rolled away from the rocket at launch time.
During Saturday’s countdown, fuel and oxidizer were loaded into both stages of the Atlas V rocket and final checks will be conducted to ensure that both AV-078 and its payload are ready for flight. About 2.7 seconds before the countdown reaches zero the Atlas V’s RD-180 engine ignited. Liftoff is expected about 3.8 seconds after ignition, when the thrust generated by the RD-180 exceeds the weight of the fully-loaded Atlas.
The RD-180 engine was built by Russia’s NPO Energomash and consists of a massive propellant pump feeding two combustion chambers burning RP-1 kerosene propellant oxidized by liquid oxygen. The RD-180 was developed from the four-chamber RD-170 that was originally designed for the first stage of the Zenit rocket which also served as a booster for the larger Energiya vehicle.
At 17.1 seconds into its mission, Atlas began a series of pitch and yaw maneuvers to attain the proper flight profile for its planned orbit. The rocket flew south-south-east from Vandenberg, on a compass course - azimuth of about 158 degrees, following the coast as it heads towards a 63.4-degree-inclined parking orbit. About 77.8 seconds after liftoff, Atlas reached Mach 1 – the speed of sound – with the rocket passing through the area of maximum dynamic pressure, or Max-Q, 9.1 seconds later.
The Common Core Booster powered Atlas for the first four minutes and 4.3 seconds of its mission before depleting its propellant. At this point, booster engine cutoff (BECO) occurred, with the CCB shutting down its engine. Six seconds after BECO, the spent first stage was jettisoned, and Centaur entered its prestart sequence.
Centaur’s RL10C-1 engine ignited for the first of its two planned burns about ten seconds after stage separation. For the InSight launch, the single-engine version of the Centaur upper stage was used. The RL10 engine is manufactured by Aerojet Rocketdyne and burns cryogenic propellant – liquid hydrogen and liquid oxygen.
Eight seconds into the second stage burn, Atlas’ payload fairing separated from around InSight. The fairing protects the spacecraft from Earth’s atmosphere and allows the rocket to present a consistent aerodynamic profile, however once Atlas reaches space the fairing is no longer needed and is discarded to save weight. Saturday’s launch used a four-meter (13-foot) diameter fairing which is mounted outside of the Centaur which attaches below the Centaur – encapsulating it along with the payload.
To launch InSight, the shortest version of Atlas V’s four-meter fairing was used. This is named the Large Payload Fairing (LPF) – as it was originally developed as an optional, larger, fairing for the Atlas I rocket. The fairing is 12.2 meters (40.0 feet) long, separated into two halves that fall away from the rocket.
Centaur’s first burn lasted eight minutes and 47.9 seconds, injecting the stage and its payload into a low Earth parking orbit. After a 65-minute, 40.70-second coast, Centaur performed its second burn. This five-minute, 22.9-second maneuver took place as the rocket flew over Siberia, propelling InSight out of Earth’s orbit.
InSight separated from Centaur nine minutes after the second burn completes – at one hour, 33 minutes and 19.8 seconds mission elapsed time. At spacecraft separation, the rocket flew over the Pacific Ocean off the west coast of the United States, having completed almost a complete orbit since liftoff. The MarCO-A CubeSat separated from a spring-loaded deployer on Centaur’s Aft Bulkhead Carrier (ABC) thirty-four seconds after InSight, with the MarCO-A being deployed forty-eight seconds later.
Timeline for Atlas V 401 launch and deployment of InSight. Note the polar transfer orbit to Mars
With its primary mission complete, Centaur performed a blowdown beginning one hour, 59 minutes and 39.8 seconds after liftoff. This passivated the stage and vent any remaining propellant. For Atlas V, the mission officially ended after two hours, 41 minutes and 19.8 seconds, with Centaur remaining in orbit around the Sun. The initial deployment orbit is designed to ensure that Centaur does not impact Mars – protecting the planet from any possible contamination – with the three spacecraft performing course correction maneuvers a few days after launch to put them on course for the Red Planet.
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