Sunkar

Project Organization

The current proposal for Sunkar is led by JSC SRC Progress, with support by Khrunichev and Makeyev, additionally, RSC Energia would handle the launch site, and supply the Blok DM-03, while Roscosmos would finance the development through the Project Fenicks under the 2016-2025 Russian space master plan. KazCosmos would also be a partner since the initial launch pad would be at Baikonur Cosmodrome Site 45 in Kazakhstan, within the framework of the Baiterek bi-national joint venture, and International Launch Services (ILS) would commercialize its services for the international market.

The initial application of the launch vehicle would be to cover the under 5 t (5.5 tons) to GTO commercial launch segment. With the loss of the Zenit-3SLB due to Russia conflicts with Ukraine, both the decision not to develop Angara A3 and launch Angara A5 from Vostochny, the Baiterek project was without a launch vehicle. The 2016 announcement of the Proton Medium and Light, meant that ILS, would enter the medium GTO launch market. But since the Kazakh government desired to deprecate the use of highly toxic hypergolic propellants used by Proton, they would need a replacement.

For this commercial application JSC SRC Progress proposed the Sunkar in early 2016. It would start with this commercial application with the prospect of also enabling a super heavy launcher with a 80 t (88 tons) payload capability to low Earth orbit. The Kazakh side agreed on the general terms, but the investment share was left to decide. As part of the 2016 arrangements, the Kazakh government would get ownership of one the Proton launch pads, and participate in the operations of Proton-Medium and Proton-Light. Then, they would get to participate in the Sunkar launchers since its expected debut in 2014.

Vehicle Description

Sunkar, as proposed in 2016, reuses many available propulsion and tooling, while enabling a platform that would replace the lost capabilities of the Zenit family, replace the Proton Light/Medium, and could serve as the boosters of a new super heavy rocket. It will initially be a two-stage rocket, but could be enhanced with an optional Blok DM-03 for geostationary missions. It would be compatible with most of the Zenit's ground infrastructure, and even use the Site 45 at Baikonur.

Its tanks would be 4.1 m (13 ft) in diameter, which would enable the re use of Proton's tooling. Since they would be wider than Zenit (3.9 m (13 ft)) it would enable a higher propellant load for the same height. While this diameter enables a heavier rocket and is already compatible with train transport to Baikonur, it would prevent that cheap method for Vostochny Cosmodrome. It would use the relatively environmental friendly RG-1/LOX propellant, which would be an improvement over the highly toxic hypergolics of Proton. This has been a requirement from the Kazakh government for new projects.

The first stage would be powered by an RD-171M (same as modern Zenit), with the option of developing a version with a 10% thrust increase, or the use of two RD-180. With a height of 37.14 m (121.9 ft) it would be higher than Zenit's first stage (32.94 m (108.1 ft)) and wider, and thus it could carry 398 t (439 tons) of propellant versus 320 t (350 tons). Its base would still feature a 3.68 m (12.1 ft) aft section for compatibility with Zeni't pad and support infrastructure.

Its second stage would measure 7.77 m (25.5 ft) by 4.1 m (13 ft) in diameter, with a dry mass of 6.5 t (7.2 tons) and an RG-1/LOX load of 60 t (66 tons). It would be powered by two RD-0124A, same as Angara. But instead of arranging the four nozzles in a square, it would feature a semicircle arrangement, so the two engines would feature the eight total nozzles close to its perimeter, forming a circle. This arrangement would minimize the stage length, while keeping the engines excellent specific impulse.

With a gross mass of 520 t (570 tons) against Zenit 474 t (522 tons), and the improved efficiency of its second stage, it could launch 17 t (19 tons) to a 200 km circular orbit with an inclination of 51.6° to the Equator from Baikonur. This is a significant improvement over Zenit, that could do roughly 13.7 t (15.1 tons) to the same orbit.

For geostationary launch missions, it could optionally be equipped with a Blok DM-03 third stage. Since it would use the same propellant and is already used on the Zenit-3SL, Proton-M and Angara A5, it would be a low risk option. The expected performance of 5 t (5.5 tons) to GTO and 2.5 t (2.8 tons) to GSO, it would improve over Zenit-3SLB 4 t (4.4 tons) and 1.75 t (1.93 tons).

Super heavy launcher evolution

Its first stage could be used as the boosters (and even core) of a super heavy rocket capable of launching 80 t (88 tons) to low Earth orbit from Baikonur or Vostochny. Improving the performance to 120 t (130 tons) and even 160 t (180 tons) was considered possible with this architecture. While the current 2016-2025 plan for deep space exploration calls for the use of the heavy Angara 5V, it would just enable 37 t (41 tons), requiring up to four launches for a single Moon mission. And would also require the use of expensive hydrogen as fuel. The Sunkar-based super heavy would simplify the mission while using readily available modules.