Effects of spaceflight and simulated microgravity on microbial growth and secondary metabolism

Spaceflight and ground-based microgravity analog experiments have suggested that microgravity can affect microbial growth and metabolism. Although the effects of microgravity and its analogs on microorganisms have been studied for more than 50 years, plausible conflicting and diverse results have frequently been reported in different experiments, especially regarding microbial growth and secondary metabolism. Until now, only the responses of a few typical microbes to microgravity have been investigated; systematic studies of the genetic and phenotypic responses of these microorganisms to microgravity in space are still insufficient due to technological and logistical hurdles. The use of different test strains and secondary metabolites in these studies appears to have caused diverse and conflicting results. Moreover, subtle changes in the extracellular microenvironments around microbial cells play a key role in the diverse responses of microbial growth and secondary metabolisms. Therefore, "indirect" effects represent a reasonable pathway to explain the occurrence of these phenomena in microorganisms. This review summarizes current knowledge on the changes in microbial growth and secondary metabolism in response to spaceflight and its analogs and discusses the diverse and conflicting results. In addition, recommendations are given for future studies on the effects of microgravity in space on microbial growth and secondary metabolism.

论Manned Spaceflight的文体特征及其翻译策略——以被动句为研究案例

Manned Spaceflight一文陈述客观准确,逻辑结构严密,专业术语性强,语气正式。其文体特征包括被动语态、名词化、非谓语、专业词汇、割裂、并列、无灵主语、介词、长句、省略等。以被动句为例,通过Manned Spaceflight中翻译实践发现,被动句翻译为主动句、被动句和无主句时,翻译策略各不相同。

Analyses on schedule-cost coefficient correlation of spaceflight project based on historical statistics and its application

When analyze the uncertainty of the cost and the schedule of the spaceflight project, it is needed to know the value of the schedule-cost correlation coefficient. This paper deduces the schedule distribution, considering the effect of the cost, and proposes the estimation formula of the correlation coefficient between the in（schedule） and the cost. On the basis of the fact and Taylor expansion, the relation expression between the schedule-cost correlation coefficient and the in-schedule-cost correlation coefficient is put forward. By analyzing the value features of the estimation formula of the in-schedule-cost correlation coefficient, the general rules are proposed to ascertain the value of the schedule-cost correlation coefficient. An example is given to demonstrate how to approximately amend the schedule-cost correlation coefficient based on the historical statistics, which reveals the traditional assigned value is inaccurate. The universality of this estimation method is analyzed.

Mutagenic Effects of Spaceflight Treatment on the Second-Generation Seeds of Alfalfa

[ Objective] To explore the effects of spaceflight on the second-generation seeds of alfalfa and provide a theoretical basis for mutation breeding. [Method] The seeds of Medicago stavia L. lines no. 1, no. 2 and no. 4 were carried into space by the Shijian-8 seed breeding satellite for a 15-d spaceflight treatment. After returning to the ground, seedlings were transplanted to field. Traits of the second-generation seeds of alfalfa were evaluated. [Result] The 1 000-grain weight of the second-generation seeds were 5% -9% significantly higher than that the control （P 〈 0.05）. The germination rate, seedling weight, shoot length and root length were significantly increased （P 〈 0.05）. The hard seed rate and the rate of moldy seeds were significantly decreased （ P 〈 0.05）. However, the rate of dead seeds was increased. [ Conclusion] Spaceflight treatment has positive mutagenic effects on the second-generation seeds of alfalfa.

Speed kills: Highly relativistic spaceflight would be fatal for passengers and instruments

Highly relativistic speeds are desirable for interstellar travel. Relativistic time dilation would reduce the subjective duration of the trip for the travelers, so that they can cover galaxy-scale distances in a reasonable amount of personal time. Unfortunately, as spaceship velocities approach the speed of light, interstellar hydrogen H, although only present at a density of approximately 1.8 atoms/cm3, turns into intense radiation that would quickly kill passengers and destroy electronic instrumentation. In addition, the energy loss of ionizing radiation passing through the ship’s hull represents an increasing heat load that necessitates large expenditures of energy to cool the ship. Stopping or diverting this flux, either with material or electromagnetic shields, is a daunting problem. Going slow to avoid severe H irradiation sets an upper speed limit of v ~ 0.5 c. This velocity only gives a time dilation factor of about 15%, which would not substantially assist galaxy-scale voyages. Diffuse interstellar H atoms are the ultimate cosmic space mines and represent a formidable obstacle to interstellar travel.

Manned Spaceflight Ancient Dream, Modern Attempt

China was first in the world to invent rockets, and the first "astronaut" was also Chinese. In the late 14th century a man named Wanhu had himself tied to a special chair, the back of which was fitted with 47 prototype rockets, while

Estimation Method of Schedule-cost Correlation Coefficient of Spaceflight Project

To evaluate the cost risk and the schedule risk of the spaceflight project,the schedule-cost(S-C) correlation coefficient is directly appointed according to the experts' experience usually.This paper deduces SDMCU(the schedule distribution model considering the effect of the cost uncertainty),and then proposes the approximate formula to estimate the ln(S)-C correlation coefficient based on the models of SDMCU and CDMSU(the cost distribution model considering the effect of the schedule uncertainty).Furthermore,an approximate relationship expression of the S-C and the ln(S)-C correlation coefficients is put forward according to general facts and the Taylor expansion,and advanced by means of mass numerical validation is the general rule of obtaining the estimation value of the schedule-cost correlation coefficient based on the historical data.

Remarkable Achievements of China’s Manned Spaceflight Project

On September 21,1992, the feasibility report on implementing China's Manned Spaceflight Project was approved and a three-step development strategy was also determined. From then on, China's Manned Spaceflight Project has developed rapidly.

LM-2F: A Great Launch Vehicle for China's Manned Spaceflight

The LM-2F launch vehicle is China's first launch carrier developed for China's Manned Space Program,which is one of the most important parts of the Program.It is developed from the LM-2E launch vehicle,with addition of two new systems,an escape system and a fault detection system.

Genome and clonal hematopoiesis stability contrasts with immune,cfDNA,mitochondrial,and telomere length changes during short duration spaceflight

Background The Inspiration4(I4)mission,the first all-civilian orbital flight mission,investigated the physiological effects of short-duration spaceflight through a multi-omic approach.Despite advances,there remains much to learn about human adaptation to spaceflight's unique challenges,including microgravity,immune system perturbations,and radiation exposure.Methods To provide a detailed genetics analysis of the mission,we collected dried blood spots pre-,during,and post-flight for DNA extraction.Telomere length was measured by quantitative PCR,while whole genome and cfDNA sequencing provided insight into genomic stability and immune adaptations.A robust bioinformatic pipeline was used for data analysis,including variant calling to assess mutational burden.Result Telomere elongation occurred during spaceflight and shortened after return to Earth.Cell-free DNA analysis revealed increased immune cell signatures post-flight.No significant clonal hematopoiesis of indeterminate potential(CHIP)or whole-genome instability was observed.The long-term gene expression changes across immune cells suggested cellular adaptations to the space environment persisting months post-flight.Conclusion Our findings provide valuable insights into the physiological consequences of short-duration spaceflight,with telomere dynamics and immune cell gene expression adapting to spaceflight and persisting after return to Earth.CHIP sequencing data will serve as a reference point for studying the early development of CHIP in astronauts,an understudied phenomenon as previous studies have focused on career astronauts.This study will serve as a reference point for future commercial and non-commercial spaceflight,low Earth orbit(LEO)missions,and deep-space exploration.

On-orbit sleep problems of astronauts and countermeasures

Sufficient sleep duration and good sleep quality are crucial to ensure normal physical and mental health, cognition and work performance for the common people, as well as astronauts. On-orbit sleep problem is very common among astronauts and has potential detrimental influences on the health of crewmembers and the safety of flight missions. Sleep in space is becoming a new medical research frontier. In this review we summarized on-orbit sleep problems of astronauts and six kinds of causes, and we presented the effects of lack of sleep on performance as well as mental and physical health, then we proposed seven kinds of countermeasures for sleep disturbance in spaceflight, including pharmacologic interventions, light treatment, crew selection and training, Traditional Chinese Medicine and so on. Furthermore, we discussed and oriented the prospect of researches on sleep in space.

Mars Orbiter magnetometer of China’s First Mars Mission Tianwen-1

As one of the seven scientific payloads on board the Tianwen-1 orbiter,the Mars Orbiter Magnetometer(MOMAG)will measure the magnetic fields of and surrounding Mars to study its space environment and the interaction with the solar wind.The instrument consists of two identical triaxial fluxgate magnetometer sensors,mounted on a 3.19 meter-long boom with a seperation of about 90 cm.The dual-magnetometers configuration will help eliminate the magnetic field interference generated by the spacecraft platform and payloads.The sensors are controlled by an electric box mounted inside the orbiter.Each magnetometer measures the ambient vector magnetic field over a wide dynamic range(to 10,000 nT per axis)with a resolution of 1.19 pT.Both magnetometers sample the ambient magnetic field at an intrinsic frequency of 128 Hz,but will operate in a model with alternating frequency between 1 and 32 Hz to meet telemetry allocations.

Molecular Variation and Application from Aerospace Mutagenesis in Upland Rice Huhan 3 and Huhan 7

To further improve upland rice varieties Huhan 3 and Huhan 7, seed samples were sent to outer space with two recoverable spaceships for approximately 1 and 5 d and were propagated for 7 and 5 generations, respectively. Phenotypic analysis revealed that the morphological traits and the protein and amylose contents of grains changed. Characterization of genomic mutations by the gene-associated simple sequence repeat （SSR） and insertion-delete （InDel） markers indicated that the mutation pattern was very complex. Most of the mutations occurred at the 3＇- or 5＇-end of the fragments in the simple sequence repeat fragment. Reverse transcription-polymerase chain reaction （RT-PCR） assay showed that mutations in those parts of the SSR affected their gene expression, indicating that gene associated markers would be helpful to isolate functional genes. Field survey for breeding also revealed that more lines with high yield, high quality and drought-tolerance could be selected through aerospace breeding. The results indicate that aerospace mutagenesis resulted in molecular variation, as well as physiological and morphological changes for rice breeding.

Non-invasive panel tests for gastrointestinal motility monitoring within the MARS-500 Project

AIM:To develop an integrated approach for monitoring gastrointestinal motility and inflammation state suitable for application in long-term spaceflights.METHODS:Breath tests based on the oral administration of 13 C-labeled or hydrogen-producing substrates followed by the detection of their metabolites(13 CO 2 or H 2) in breath were used to measure gastrointestinal motility parameters during the 520-d spaceflight ground simulation within the MARS-500 Project.In particular,the gastric emptying rates of solid and liquid contents were evaluated by 13 C-octanoic acid and 13 Cacetate breath tests,respectively,whereas the orocecal transit time was assessed by an inulin H 2-breath test,which was performed simultaneously with the 13 C-octanoic acid breath test.A ready-to-eat,standardized pre-packaged muffin containing 100 mg of 13 C-octanoic acid was used in the 13 C-octanoic acid breath test to avoid the extemporaneous preparation of solid meals.In addition,a cassette-type lateral flow immunoassay was employed to detect fecal calprotectin,a biomarker of intestinal inflammation.Because no items could be introduced into the simulator during the experiment,all materials and instrumentation required for test performance during the entire mission simulation had to be provided at the beginning of the experiment.RESULTS:The experiments planned during the simulation of a manned flight to Mars could be successfully performed by the crewmembers without any external assistance.No evident alterations(i.e.,increasing or decreasing trends) in the gastric emptying rates were detected using the 13 C-breath tests during the mission simulation,as the gastric emptying half-times were in the range of those reported for healthy subjects.In contrast to the 13 C-breath tests,the results of the inulin H 2-breath test were difficult to interpret because of the high variability of the H 2 concentration in the breath samples,even within the same subject.This variability suggested that the H 2-breath test was strongly affected by external factors,which may have been related to the diet of the crewmembers or to environmental conditions(e.g.,the accumulation of hydrogen in the simulator microenvironment).At least in closed microenvironments such as the MARS-500 simulator,13 C-breath tests should therefore be preferred to H 2-breath tests.Finally,the fecal calprotectin test showed significant alterations during the mission simulation:all of the crewmembers were negative for the test at the beginning of the simulation but showed various degrees of positivity in at least one of the subsequent tests,thus indicating the onset of an intestinal inflammation.CONCLUSION:Breath tests,especially those 13 Cbased,proved suitable for monitoring gastrointestinal motility in the 520-d isolation experiment withinMARS-500 project and can be applied in long-term spaceflights.

National Report on Space Medicine Progress in 2012–2014

The application of manned spaceflight makes a great impetus on the development of space medicine. With the deep growth of Chinese manned space, our national space medicine has attained great achievements. In this paper, the basic research of Space Medicine and its application in China during 2012–2014 were briefly reviewed.

National Report on Space Medicine Progress in 2010—2012

Accompanying the flourishing developments of China's manned spaceflight,space medicine has achieved great development during the past two years in China.In this paper,scientific research of space medicine and its application in China during 2010-2012 have been briefly introduced.

Analysis of Human Reliability Model in Manned Vehicle

A typical man-machine-environment system is composed of astronaut, vehicle and space environment in the course of manned spaceflight. In this paper, the important role played by man and the factors on his capability in vehicle system have been described, and a stress-strength human reliability model is also put forward. In the end, it must be systematically considered to raise the astronaut's reliability.

Safe Return

Zhai Zhigang, taikonaut of China’s Shenzhou-13 manned spaceflight mission, exits the return capsule on April 16.Zhai and two other taikonauts, Wang Yaping and Ye Guangfu, touched down at the Dongfeng landing site in Inner Mongolia Autonomous Region in north China after a six-month mission. They are the second crew sent to orbit for space station construction.

神舟十三号飞船推进系统综述

Based on the requirements of manned spaceships,this paper introduces the characteristics of the propulsion system from the perspectives of design scheme,basic composition,safety and reliability measures,and also introduces the ground test verification and on-orbit flight characteristics of the Shenzhou 13 propulsion system.According to the flight results,it was seen that the performance of the Shenzhou 13 propulsion system fully met the engineering requirements for the manned space mission.

Physiological effects of weightlessness: countermeasure system development for a long-term Chinese manned spaceflight

The Chinese space station will be built around 2020. As a national space laboratory, it will offer unique opportunities for studying the physiological effects of weightlessness and the efficacy of the countermeasures against such effects. In this paper, we described the development of countermeasure systems in the Chinese space program. To emphasize the need of the Chinese space program to implement its own program for developing countermeasures, we reviewed the literature on the negative physiological effects of weightlessness, the challenges of completing missions, the development of countermeasure devices, the establishment of countermeasure programs, and the efficacy of the countermeasure techniques in American and Russian manned spaceflights. In addition, a brief overview was provided on the Chinese research and development on countermeasures to discuss the current status and goals of the development of countermeasures against physiological problems associated with weightlessness.