Issue No. 70

The Orbital Index

Issue No. 70 | Jun 24, 2020

🚀 🌍 🛰

How is Perseverance different from Curiosity? As Perseverance nears launch-readiness, we look at the differences 9 years make in the tech and mission of a Mars rover. Curiosity focused on gauging the past habitability of Gale Crater, finding an ancient, potentially habitable river and intermittent lake system. Like its closely-related predecessor, Perseverance will also gauge habitability of its landing region (Jezero Crater, a paleo-lakebed with preserved river delta and sediments). But, it will go further by directly hunting for ancient microbial biosignatures (with lasers!) and storing the most interesting samples in 20 sealed caches on the Martian surface for a future sample return mission (tentatively launching in 2026). Perseverance is phenomenally complex, its Sample Caching System alone contains 3,000+ parts and two robotic arms. Perseverance is based on Curiosity’s design, but has redesigned & more durable aluminum wheels, better skycrane and landing navigation systems, additional improved cameras, Mars’ first microphones, a larger drill (that can “cut intact rock cores, rather than pulverizing them”), an ISRU experiment that makes oxygen from CO2, more advanced autonomous navigation, and a very different set of instruments. Both rovers are powered by a Multi-Mission Radioisotope Thermoelectric Generator (MMRTG), allowing full time operation, with Perseverance carrying a unit left over from Curiosity. Oh, and Perseverance has a helicopter drone (cf. Issue 64)! Perseverance is scheduled to launch at 9:15 a.m. EDT July 20—any later than mid-August and it’ll need to wait two years for the next Mars launch window. If the flight goes as planned, it will land in Mars' Jezero Crater on Feb. 18, 2021.

How would the Mars Sample Return mission work? NASA recently settled on a solid-fuel design for their Mars Ascent Vehicle (MAV), the small (max 400 kg), two-stage rocket that will hopefully carry the samples, left on the surface of Jezero Crater by Perseverance, into orbit. Once there, it will perform the first autonomous rendezvous between two spacecraft beyond the Earth-Moon system, and transfer its samples into the care of ESA’s electrically-propelled Earth Return Orbiter (ERO). Solid fuel was selected because it needs to remain stable through the years of “cold soak” temperatures in space (-156° C) and on Mars—it’d launch in 2026, but not be fired up until 2029. Samples, carried by ERO, would later enter Earth’s atmosphere over Utah in a heat-shielded capsule in 2031. Here’s a video about the complex mission architecture from ESA.

A concept image of the Mars Sample Return mission including NASA's Mars Ascent Vehicle, ESA's Earth Return Orbiter, the Mars sample canister, and the Earth entry capsule.

See the edge of space in the balloon-born Spaceship Neptune. Last week, Space Perspectives revealed plans for a balloon-lofted suborbital space capsule. The capsule would take 8 passengers, a pilot, and research payloads on a 6-hour ride up to 30 km and then splash down for ship-based recovery (video). While only a third of the way to the Kármán line, it is high enough to observe the curvature of the earth with a black sky overhead. The capsule, which won't require special suits for passengers, would be equipped with a 360° viewing dome, seats that recline for landing, and a bar. Space Perspective's founders were part of the team behind Biosphere 2 and have revived this idea after their 2013 startup, World View, ended up launching uncrewed balloon-based platforms that station-keep for up to a month instead of humans. Seats on SS Neptune are expected to cost about $125,000, with initial launches from KSC. The balloon inflates to the size of a football stadium and uses hydrogen lifting gas due to its cost and environmental benefits over helium. One last important detail: the capsule does feature a toilet that may have the “best view of any loo in the world.” 🚽✨ A first uncrewed test flight is scheduled for early 2021.

News in brief. A (very experimental) quantum cryptographic link using entangled photons was established between two ground stations 1,200 km apart via the Chinese Micius satellite (paper); a Chinese Gaofen-9 Earth observation satellite launched, as well as the final BeiDou navigation satellite—see China NewSpace’s coverage; the solid rocket boosters for Artemis 1 and OmegA arrived by train at KSC; Redwire, a conglomeration of small space companies, acquired Made In Space; SpaceX announced that they have booked over 100 spacecraft for rideshare missions (likely with a significant bump from their new deal with Spaceflight), and are planning another Starlink launch for tomorrow; and, NASA released an RFI for suborbital transportation services with the goal of flying astronauts on SpaceShipTwo and New Shepard.

A HiRISE image taken by NASA’s Mars Reconnaissance Orbiter (MRO) of sediments, created by wind or water, in the Meridiani Planum region near where Opportunity landed in 2004.

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