Issue No. 262

The Orbital Index

Issue No. 262 | Mar 27, 2024

🚀 🌍 🛰

Goodbye, Delta. The last of the long-lived Delta family of rockets is scheduled to launch tomorrow. The final Delva IV Heavy will take off from Cape Canaveral Space Force Station NET 1:40 p.m. EDT (video stream; launch is pending weather that’s only 30% favorable for an on-time liftoff). The mission will deliver a classified NRO payload to (an also classified) orbit. The Delta family was first launched almost 65 years ago in 1960, converting Douglas Aircraft’s (later McDonnell Douglas, then Boeing, and now ULA) hurriedly-developed and failure-prone Thor intermediate-range ballistic missile into the first stage of an orbital-class launch vehicle. The first Thor DM-19 Delta variant could place just 45 kg into GTO—but almost innumerable iterations over the intervening 64 years have eventually yielded a final variant with little relation to the original, capable of carrying 13,810 kg into GTO. Delta IV Heavy uses three side-by-side Common Booster Cores (CBCs) shared with its Medium configurations, the last of which flew in 2019. With tomorrow’s launch, 77 CBCs will have been launched across the three variants since the booster’s first static fire in 2001. The Heavy variant’s unique three liquid-fueled booster configuration clearly influenced SpaceX’s development of Falcon Heavy and was perhaps itself influenced by Proton-M’s six-booster cluster configuration. Delta IV has always been a particularly expensive rocket, though, relying on the hydrolox RS-68A engine (initially developed with the intention of being a “cheaper” version of the RS-25 Space Shuttle Main Engine). Due to a cost of $165M+, or up to $440M for a single Heavy launch, the US government has paid for every Delta IV launch except its maiden launch of Eutelsat W5. Tomorrow’s final Delta IV Heavy launch should be a typically fiery affair. The rocket flows liquid hydrogen through the engines to purge oxidizer prior to launch, creating a cloud of H2 that the rocket ignites as it lifts off, enveloping it in an iconic fireball—a fittingly fiery departure in Viking fashion for a rocket initially named after the Norse god of thunder. 🔥🚀

The long history of the Thor-Delta family of rockets. 

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We recommend avoiding spacetimes considered unstable, unpredictable, or “tachyons only”. More than 1 time dimension seems… awkward… in general.

News in brief. China launched their Queqiao-2 relay satellite (which we wrote about recently) to support future lunar missions and it entered lunar orbit China also launched a second batch of (likely-military) Yunhai-2 satellites with radio occultation sensors for weather forecasting Northrop Grumman is studying a “Lunar Railroad” on behalf of DARPA SpaceX’s “Plug and Plaser” offering makes the laser comms system developed for Starlink available to other commercial companies JPL awarded Airbus with a contract to build the GRACE-C twin spacecraft that will continue the series of GRACE missions to monitor Earth’s gravitational field (cf. Issue 118) Rocket Lab launched an Electron from LC2 at the Mid-Atlantic Regional Spaceport on Wallops Island, Virgina for the NRO Varda Space confirmed that they successfully made drugs in microgravity Intuitive Machines has stopped trying to contact Odysseus after it was powered down during the lunar night and did not phone home afterward, officially concluding the IM-1 mission (JAXA is also trying to re-contact SLIM after its second lunar night) Munich-based startup Blackwave raised $6.6M to expand production of their carbon-fiber high pressure tanks (COPVs) for satellites and launch vehicles SpaceX launched a Cargo Dragon resupply mission to the ISS and conducted a full-duration static fire of all six of Ship 29’s engines in preparation for Starship Flight 4 (Booster 11 is up next) A Soyuz launch to the ISS was aborted 20 seconds before takeoff due to a low voltage reading in the rocket’s electrical system — but later flew successfully, taking two-short duration crew members and a US astronaut to the ISS.

A Soyuz rocket lifting off from Baikonur Cosmodrome in Kazakhstan, sending the Soyuz M-25 crewed spacecraft to the ISS.

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This is a 1.3 gigapixel image of the 11,000-year-old Vela Supernova Remnant taken by DECam at the Cerro Tololo Inter-American Observatory in Chile. Consider it your new desktop background.

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