Launch Roundup: Delta IV swan song, Angara test flight from Russia, and three Falcon 9 flights


The second week of April not only has a long-awaited total solar eclipse but also orbital launches from Russia and the United States. Besides the long-awaited NROL-70 Delta IV Heavy finale, there was to be a test flight of the Russian Angara rocket from the Vostochny Cosmodrome in Russia and a handful of Falcon 9 launches. Delta IV Heavy’s final flight with a mission for the National Reconnaissance Office on Tuesday, April 9 has now taken place.

The NROL-70 and Angara flights were both scheduled for Tuesday, April 9 – although the latter scrubbed with a few minutes remaining in the count – while Starlink Group 6-48 is set to fly on Wednesday, April 10, from the Cape Canaveral Space Force Station (CCSFS) in Florida. Another Falcon 9 with the USSF-62/WSF-M1 mission is scheduled for Thursday, April 11, from Vandenberg Space Force Base (VSFB) in California. Yet another Starlink launch — Starlink Group 6-49 — is set for Friday, April 12, from the Kennedy Space Center (KSC) in Florida.

Render of the Angara A5. (Credit: Mack Crawford for NSF/L2)

Khrunichev Angara A5/Blok DM-03 | Test Flight

The Angara family of rockets is about to make one of its rare flights and its first from Vostochny Cosmodrome in eastern Russia. The first of possibly two Angara flights in 2024 was scheduled for Tuesday, April 9, from Vostochny’s Site 1A. No launch time has been officially made available yet, but the Russian news agency TASS has stated that the flight is scheduled for approximately 09:00 UTC. However, with a few minutes remaining in the count, the launch was scrubbed.

This Angara flight will not carry any payloads but will fly an “Orion” upper stage that is thought to be similar to the Persei upper stage that flew on the last Angara A5 flight in late 2021. A mass simulator known as GMM KA will also be carried. Russia was hoping to start operational A5 flights after three tests, but the third A5 launch failed when the upper stage failed to restart on orbit, leaving the stage in low-Earth orbit. This week’s Angara flight, therefore, will be a repeat of the third test for this variant.

If this flight succeeds, the next A5 flight is set for no earlier than December of this year and will carry the Tundra No. 7L early warning and secure communications satellite to a high-latitude and high-altitude “Molniya” elliptical orbit.

This flight will be the fourth flight of the A5 variant and the seventh flight of the Angara family overall. All previous flights of the Angara family have been from the Plesetsk Cosmodrome in northern Russia, which mainly serves missions bound for polar orbits. Vostochny was created to allow launches to other orbital inclinations from Russian territory instead of having to launch from the Baikonur Cosmodrome in Kazakhstan.

Maiden launch of the Angara A5 rocket in Dec. 2014. (Credit: Roscosmos)

The Angara family, meant to replace multiple Soviet-era launchers, is based on a core vehicle known as the Universal Rocket Module-1 (URM-1). Each URM-1 uses a single NPO Energomash RD-191 rocket engine capable of producing 1,920 kilonewtons of thrust. The engine uses RG-1 — a form of kerosene — and liquid oxygen as propellants.

Angara’s second stage is the Universal Rocket Module-2 (URM-2), equipped with one RD-0124A engine that produces 294.3 kilonewtons of thrust. Like the URM-1, the URM-2’s engine also uses RG-1 and liquid oxygen as propellants. Depending on the mission and configuration, an optional third stage can be added to the rocket stack.

Models of the Angara family of rockets being shown by Roscosmos at MAKS 2021. (Credit: Kirill Borisenko)

Although up to seven variants of Angara have been proposed, only two have flown so far. The Angara 1.2 uses one URM-1 as the first stage and a modified Block I stage as the second stage, while the Angara A5 uses four URM-1s as strap-on boosters attached to the URM-1 core and a URM-2 as the second stage. The Angara A5 can also use a third stage, and the rocket has flown with the Briz-M or Persei upper stages.

Angara was intended to be a modular family of rockets with an approach similar to United Launch Alliance’s “dial-a-rocket” strategy for the Atlas V. The Angara A5 will eventually replace the Proton rocket, which served as the Soviet and Russian heavy-lift launcher for many years, while the Angara 1.2 is comparable to the Dnepr rocket that is based on the SS-18 ICBM. Whether any other version of Angara flies remains to be seen.

Delta IV Heavy being prepared for its final flight on NROL-70. (Credit: ULA)

ULA Delta IV Heavy|NROL-70

The long-awaited – and delayed – 389th and final launch of the Delta family successfully happened on Tuesday, April 9. NROL-70, aboard the last ever Delta IV Heavy, flew at 12:53 PM EDT (16:53 UTC) from CCSFS SLC-37B. The first and only flight of the Delta IV Heavy in 2024 marks the end of a rocket family that dates back to near the beginning of the Space Age.

NROL-70 had been counting down to a launch attempt on March 28 when high winds forced a hold in the count just after it had restarted from the T-4 minute mark. A pump for a gaseous nitrogen pipeline failed forcing a scrub. A replacement pump that would have allowed a 24-hour recycle did not work and it took a number of days for the problem to be fixed.

The Delta IV Heavy flew due east, which is consistent with other flights of this type that have flown from CCSFS with the Orion series of intelligence satellites that have flown to geostationary orbit. After this mission, the Vulcan family will replace the Delta IV Heavy’s capabilities. Vulcan eventually will also replace the Atlas family, while there are plans for SLC-37B to be taken over by SpaceX.

Starlink v2 Mini satellites prior to deployment (Credit: SpaceX)

Starlink v2 Mini satellites prior to deployment. (Credit: SpaceX)

SpaceX Falcon 9 | Starlink Group 6-48

The first flight of the week for Falcon 9 will be the Starlink Group 6-48 mission, set for launch on Wednesday, April 10, at the beginning of a four-hour, 31-minute window starting at 12:00 AM EDT (04:00 UTC) from Space Launch Complex (SLC) 40 at CCSFS. The nighttime launch will be taking a southeast trajectory similar to other Starlink flights of this group, with the Starlink v2 Mini satellites targeting insertion into an orbit inclined 43 degrees to the equator.

The booster, whose identity is not yet known, is scheduled to land on the droneship Just Read The Instructions, which will be stationed several hundred miles downrange in the Atlantic. The droneship and support ship Bob departed Port Canaveral last week to support this mission. Bob will be responsible for handling the retrieval of the two fairing halves enclosing the Starlink payload on launch.

This flight will be the 36th Falcon 9 launch of 2024 and the fifth this month. March set a record of 12 launches in one month for the Falcon family and SpaceX could meet or exceed this goal as it continues to march toward its goal of 148 total launches this calendar year.

SpaceX Falcon 9 | USSF-62/WSF-M1

Next on Falcon 9’s agenda is a mission for the United States Space Force, USSF-62. The mission is scheduled to fly from SLC-4E at VSFB on Thursday, April 11. The launch window starts at 5:00 AM PDT (12:00 UTC) and ends at 9:36 AM PDT (16:36 UTC), and the flight is set to use a southbound trajectory that will take the payload into a Sun-synchronous polar orbit.

USSF-62’s payload is a satellite known as Weather System Follow-on-Microwave 1 (WSF-M1) and is a follow-on to replace the Defense Meteorological Satellite Program’s microwave capabilities in orbit. Developed by Ball Aerospace, the satellite uses a microwave imaging radiometer and an energetically charged particle sensor space weather payload.

The booster, whose identity is not yet known, will conduct a return-to-launch-site maneuver to land at Landing Zone 4. The WSF-M1 launch will be the 37th Falcon 9 flight of 2024, the 13th Falcon 9 launch from VSFB, and the sixth of the month. SpaceX recently set a record for the quickest time between launches at SLC-4E, and the ramp-up of its VSFB operations has helped the company raise the cadence of Falcon 9 flights to its current very high level.

A Falcon 9 launches the first batch of Starlink v2 Mini satellites from Florida. (Credit: Stephen Marr for NSF/L2)

SpaceX Falcon 9 | Starlink Group 6-49

The final scheduled launch for this week is the Starlink Group 6-49 mission from Launch Complex 39A at KSC. The launch window opens on Friday, April 12, at 8:00 PM EDT (00:00 UTC Saturday, April 13) and runs until 12:31 AM EDT on Saturday, April 13 (04:31 UTC). The flight will take the same southeasterly flight path as the Starlink Group 6-48 mission that launched earlier in the week, ultimately ending up in a low-Earth orbit inclined 43 degrees to the equator.

The booster, which is not yet known, will land on the A Shortfall of Gravitas droneship downrange in the Atlantic. As of April 7 — the day after the Starlink Group 8-1 launch — there have been 6,166 Starlink satellites launched and there are currently 5,765 satellites in orbit and 5,177 satellites in operational orbits. This flight will be the third Falcon 9 launch of this week, the 38th flight for the Falcon family in 2024, and the seventh of April with just over half the month to go.

(Lead image: Angara A5 on the launch pad. Credit: Roscosmos)

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