JAXA+ | What if Japan had an unlimited space budget? | 2048-12-20 - Massive crewed missions to Venus, Mars, the Moon, and the asteroid belt! [VIDEO]

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2045-12-14 - The Koujin crew transport arrived at Vesta. The last of the Earth Departure Stage's fuel was used to brake about 200 m/s, then detached. The Asteroid Orbit Stage burned for over 4500 m/s of Delta-v, making several maneuvers to intercept the Landing Module in low Vesta orbit (90 km) on December 17. Once it got close, the lander performed an automated docking with the transport. Heisuke Koishi, Takeshi Kakoi, and Rena Minase boarded the lander, which undocked and de-orbited using five LEROS-4 engines (1.3 kN each) to land in Marcia Crater on December 18. After planting the flag, the crew made long, floating strides in the low gravity to the Habitation Module (over 100 m away), which they would stay in for over 9 months.

At the same time, the Inari mission was getting ready to send another three astronauts to Ceres.

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Using the last of the Earth Departure Stage's fuel

Earth Return Stage used for rendezvous

Landing Module (arrived in 2044) docks

De-orbit

Heading to the base

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2045-07-24 - Several months before the Koujin mission landed people on Vesta, construction of the Inari Ceres transport had already begun.

2045-12-13 - After assembly and refueling, the crew of the Inari mission lifted off. Kei Nagase, Takahide Ishikawa, and Hikari Tsuchiyama docked to the massive vessel. On December 21, the spacecraft began its two-part transfer burn to Ceres, to arrive in February 2047.

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2045-07-24 - Earth Return / Asteroid Orbit stages

2045-08-20 - Earth Departure Stage

2045-09-12 - Earth Departure Stage Booster 1

2045-10-06 - Earth Departure Stage Booster 2

2045-10-30 - First refueling tanker

2045-11-22 - Second refueling tanker

2045-12-13 - Crew launch

2045-12-22 - Second Earth departure burn

 

[BrobDingnag]

9 months at 0.025 g? How’re they going to maintain their muscle and bone masses? I’d think one of the greatest challenges would be simply moving around on the surface. The same will go for Ceres (I didn’t know, until I looked it up, that Vesta and Ceres have roughly the same gravity, despite the significant size–and therefore density–difference. Interesting!), too.

 

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9 months at 0.025 g? How’re they going to maintain their muscle and bone masses? I’d think one of the greatest challenges would be simply moving around on the surface. The same will go for Ceres (I didn’t know, until I looked it up, that Vesta and Ceres have roughly the same gravity, despite the significant size–and therefore density–difference. Interesting!), too.

At this point, I was thinking that they would have cybernetic implants (developed in the 2030s) that assist bodily functions in low gravity (this was a plot point in a 2022 animated series called The Orbital Children, which also takes place in 2045).
There is also enough gravity to "walk," although it's very slow and floaty.

2045-12-24 - Heisuke Koishi, Rena Minase, and Takeshi Kakoi boarded the Vesta Cruiser and drove over 10 km to the east in Marcia Crater, which was the largest and youngest of the three "snowman craters," the others being Calpurnia and Minucia. The surface of the crater is mostly made of basaltic rock (known as eucrite) and is rich in iron. Due to the low gravity, wheel traction was also lower, and the motor was set to 5% of normal power to avoid excess torque.

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2046-09-20 - After nine months, the three crew members left the surface habitat, using the small landing module to easily launch back into orbit and dock with the interplanetary transport. On September 26, the transport ignited its single LE-N2 engine to return to Earth (~4800 m/s).

2046-09-26 - Departure from Vesta

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2047-02-07 - After 1 year and 2 months, the Inari crew transport finally arrived at Ceres, slowing down by over 5000 m/s to meet up with the landing module in a 90 km orbit on February 9. On February 10, the powered descent and landing commenced. Kei Nagase, Takahide Ishikawa, and Hikari Tsuchiyama became the first Japanese astronauts to set foot on the largest object in the asteroid belt. Over the next 6 months (a shorter stay due to transfer windows), they would live in the surface base on Occator Crater. On February 15, they explored the crater in the Ceres Cruiser, driving 20 km south and up the central hill. Occator was known for its bright spots, which were made of salt deposits (mostly sodium carbonate) left behind when briny underground water rose to the surface through cryovolcanism. The water had already sublimated into the vacuum of space, and the process could still be happening today.

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2047-08-06 - The Koujin Vesta crew transport returned to Earth after a journey of over 3 years. The Earth Arrival Vehicle undocked and decelerated by over 4000 m/s using its LE-N engine. After the capsule separated, the nuclear stage boosted out of the way to avoid entering Earth's atmosphere. Heisuke Koishi, Takeshi Kakoi, and Rena Minase splashed down off the western coast of Borneo in Indonesia.

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2047-08-10 - The crew of the Inari mission only stayed six months on Ceres, due to the different launch windows from Vesta. The next launch windows were 4 months from now (requiring an additional 1000 m/s in Delta-v for the Ceres-Earth transfer), or waiting another one-and-a-half years. After docking with the transport, they began their return trip on August 16.

2047-08-16 - Leaving Ceres

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2048-12-20 - After over another year in space, Kei Nagase, Takahide Ishikawa, and Hikari Tsuchiyama undocked in the Earth Arrival Vehicle, slowing down by 4900 m/s before entering Earth's atmosphere and splashing down in the Caribbean Sea.

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Comparison of interplanetary ships (Mars, Venus, Vesta and Ceres)