SpaceX’s Starship is the most powerful launch system ever built, dwarfing even the mighty Saturn V both in terms of mass and total thrust. The scale of the vehicle is such that concerns have been raised about the impact each launch of the megarocket may have on the local environment. Which is why a team from Brigham Young University measured the sound produced during Starship’s fifth test flight and compared it to other launch vehicles.
Published in JASA Express Letters, the paper explains the team’s methodology for measuring the sound of a Starship launch at distances ranging from 10 to 35 kilometers (6 to 22 miles). Interestingly, measurements were also made of the Super Heavy booster as it returned to the launch pad and was ultimately caught — which included several sonic booms as well as the sound of the engines during the landing maneuver.
NASA’s upcoming Artemis I mission represents a critical milestone on the space agency’s path towards establishing a sustainable human presence on the Moon. It will mark not only the first flight of the massive Space Launch System (SLS) and its Interim Cryogenic Propulsion Stage (ICPS), but will also test the ability of the 25 ton Orion Multi-Purpose Crew Vehicle (MPCV) to operate in lunar orbit. While there won’t be any crew aboard this flight, it will serve as a dress rehearsal for the Artemis II mission — which will see humans travel beyond low Earth orbit for the first time since the Apollo program ended in 1972.
As the SLS was designed to lift a fully loaded and crewed Orion capsule, the towering rocket and the ISPS are being considerably underutilized for this test flight. With so much excess payload capacity available, Artemis I is in the unique position of being able to carry a number of secondary payloads into cislunar space without making any changes to the overall mission or flight trajectory.
NASA has selected ten CubeSats to hitch a ride into space aboard Artemis I, which will test out new technologies and conduct deep space research. These secondary payloads are officially deemed “High Risk, High Reward”, with their success far from guaranteed. But should they complete their individual missions, they may well help shape the future of lunar exploration.
With Artemis I potentially just days away from liftoff, let’s take a look at a few of these secondary payloads and how they’ll be deployed without endangering the primary mission of getting Orion to the Moon.
There’s little debate that the most exciting move in a rocket’s repertoire is when it launches itself skywards on a column of flame. But failing that, it’s still pretty interesting to see how these massive vehicles get juggled around down here on terra firma before getting fired off into the black. Which is great for anyone interested in NASA’s towering Space Launch System (SLS), as it’s been doing an awful lot of milling about on the ground for a vehicle designed to return humanity to the Moon.
Most recently, the SLS completed a trek from the iconic Vehicle Assembly Building (VAB) to launch pad 39B and back again aboard the same “crawler” that moved the Space Shuttle and Saturn V before it. While the nearly 60-year-old tracked vehicle has received some updates to carry the 98 meter (322 ft) tall booster, clearly the space agency subscribes to the “if it ain’t broke, don’t fix it” school of thought.
The ICPS being loaded onto the SLS
The SLS itself however is definitely in need of some work. The rocket was brought out to the pad for the first time on March 18th, where it was to conduct what’s known as a “wet dress rehearsal” — a test of the pre-flight operations, propellant loading, and countdown that includes everything except engine ignition. Unfortunately, the test was plagued with technical issues, and after three attempts, it was decided to bring the rocket back into the VAB to make the necessary repairs to both it and the ground support equipment.
One issue involves a valve in the Interim Cryogenic Propulsion Stage (ICPS), a propulsion module that’s being used on the early SLS flights to provide the trans-lunar injection (TLI) burn that will send the Orion spacecraft on a course towards the Moon. As the name implies, the ICPS is destined to be replaced with the larger Exploration Upper Stage on later missions. There’s also a leak on the launch tower itself that will need to be addressed. After the identified problems are repaired and some adjustments are made, the SLS will once again be rolled out to the pad to reattempt the launch rehearsal.
Now in development for over a decade, the Space Launch System has been plagued with technical issues and delays. At the same time, commercial launch providers like SpaceX have moved the state of the art forward considerably, leading many to wonder if the mind-bogglingly expensive rocket will be able to compete with in-development vehicles such as Starship and New Glenn. The fact that missions which were previously assigned to the SLS have started to get shifted over to commercial rockets would seem to indicate that even NASA is losing confidence in their flagship program.
NASA first landed a human on the moon back in 1969, and last achieved the feat in December 1972. In the intervening years, there have been few other missions to Earth’s primary natural satellite. A smattering of uncrewed craft have crashed into the surface, while a mere handful of missions have achieved a soft landing, with none successful from 1976 to 2013.
However, NASA aims to resume missions to the lunar surface, albeit in an uncrewed capacity at this stage. And you won’t have to wait very long, either. The world’s premier space agency aims to once again fly to the Moon beginning in February 2022.
These days, NASA deciding to launch one of their future missions on a commercial rocket is hardly a surprise. After all, the agency is now willing to fly their astronauts on boosters and spacecraft built and operated by SpaceX. Increased competition has made getting to space cheaper and easier than ever before, so it’s only logical that NASA would reap the benefits of a market they helped create.
So the recent announcement that NASA’s Europa Clipper mission will officially fly on a commercial launch vehicle might seem like more of the same. But this isn’t just any mission. It’s a flagship interplanetary probe designed to study and map Jupiter’s moon Europa in unprecedented detail, and will serve as a pathfinder for a future mission that will actually touch down on the moon’s frigid surface. Due to the extreme distance from Earth and the intense radiation of the Jovian system, it’s considered one of the most ambitious missions NASA has ever attempted.
With no margin for error and a total cost of more than $4 billion, the fact that NASA trusts a commercially operated booster to carry this exceptionally valuable payload is significant in itself. But perhaps even more importantly, up until now, Europa Clipper was mandated by Congress to fly on NASA’s Space Launch System (SLS). This was at least partly due to the incredible power of the SLS, which would have put the Clipper on the fastest route towards Jupiter. But more pragmatically, it was also seen as a way to ensure that work on the Shuttle-derived super heavy-lift rocket would continue at a swift enough pace to be ready for the mission’s 2024 launch window.
But with that deadline fast approaching, and engineers feeling the pressure to put the final touches on the spacecraft before it gets mated to the launch vehicle, NASA appealed to Congress for the flexibility to fly Europa Clipper on a commercial rocket. The agency’s official line is that they can’t spare an SLS launch for the Europa mission while simultaneously supporting the Artemis Moon program, but by allowing the Clipper to fly on another rocket in the 2021 Consolidated Appropriations Act, Congress effectively removed one of the only justifications that still existed for the troubled Space Launch System.
Things aren’t looking good for NASA’s Space Launch System (SLS). Occasionally referred to as the “Senate Launch System”, or even less graciously, the “Rocket to Nowhere”, the super heavy-lift booster has long been a bone of contention for those in the industry. Designed as an evolution of core Space Shuttle technology, the SLS promised to reuse existing infrastructure to deliver higher payload capacities and lower operating costs than its infamous winged predecessor. But in the face of increased competition from commercial launch providers and proposed budget cuts targeting future upgrades and expansions of the core booster, the significantly over budget and behind schedule program is in a very precarious position.
Which is not to say the SLS doesn’t look impressive, at least on paper. In its initial configuration it would easily take the title as the world’s most powerful rocket, capable of lifting nearly 105 tons into low Earth orbit (LEO), compared to 70 tons for SpaceX’s Falcon Heavy. It would still fall short of the mighty Saturn V’s 155 tons to LEO, but the proposed “Block 2” upgrades would increase SLS payload capability to within striking distance of the iconic Apollo-era booster at 145 tons. Since the retirement of the Space Shuttle in 2011, NASA has been adamant that the might of SLS was the only way the agency could accomplish bigger and more ambitious missions to the Moon, Mars, and beyond.
Or at least, they were. On March 13th, NASA Administrator Jim Bridenstine testified to Congress that in an effort to avoid further delays, the agency is exploring the possibility of sending their Orion spacecraft to the Moon with a commercial launcher. The statement came as a shock to many in the aerospace community, as it would seem to call into question the future of the entire SLS program. If commercial rockets can do the job of SLS, at least in some cases, why does the agency need it?
NASA is currently preparing a report which investigates what physical and logistical modifications would need to be made to missions originally slated to fly on SLS; a document which is sure to be scrutinized by SLS supporters and critics alike. Until the report is released, we can speculate about what this hypothetical flight to the Moon might look like.
The White House’s proposed budget for 2020 is out, and with it comes cuts to NASA. The most important item of note in the proposed budget is a delay of the Space Launch System, the SLS, a super-heavy lifting launch vehicle designed for single use. The proposed delay would defer work on the enhanced version of the SLS, the Block 1B with the Exploration Upper Stage.
The current plans for the Space Launch System include a flight using NASA’s Orion spacecraft in June 2020 for a flight around the moon. This uncrewed flight, Exploration Mission 1, or EM-1, would use the SLS Block 1 Crew rocket. A later flight, EM-2, would fly a crewed Orion capsule around the moon in 2022. A third proposed flight in 2023 would send the Europa Clipper to Jupiter. The proposed 2020 budget puts these flights in jeopardy.
